YAML Formats

This page is the canonical reference for all rtl_buddy configuration files. Use it when creating or updating configs for new designs, suites, and regressions.

root_config.yaml

The root config lives at the project root. It defines platforms, builders, Verible, coverage, synthesis tools, synthesis libraries, and the default regression config path.

Required keys:

rtl-buddy-filetype: project_root_config
cfg-platforms
cfg-rtl-builder
cfg-verible
cfg-rtl-reg

Full example:

rtl-buddy-filetype: project_root_config

cfg-platforms:
  - os: "osx"
    unames: ["Darwin"]
    builder: "verilator"
    verible: "verible-macos"

cfg-rtl-builder:
  - name: "verilator"
    builder: "verilator"
    builder-simv: "obj_dir/simv"
    sim-rand-seed: 31310
    sim-rand-seed-prefix: "+verilator+seed+"
    builder-opts:
      debug:
        compile-time: "--binary -sv -o simv"
        run-time: "+verilator+rand+reset+2"
      reg:
        compile-time: "--binary -sv -o simv"
        run-time: "+verilator+rand+reset+2"

cfg-verible:
  - name: "verible-macos"
    path: "/opt/homebrew/bin"
    extra_args:
      lint:
        - "--rules=-module-filename"

cfg-coverage:
  - name: "verilator"
    use-lcov: true

cfg-coverview:
  - name: "verilator"
    generate-tables: "line"
    config:
      # inline Coverview JSON configuration values

cfg-surfer:
  - name: "surfer-default"
    path: "surfer"              # bare name → found via PATH; or relative/absolute path
    wcp-port: 0         # 0 = OS auto-assigns a free port
    editor-cmd: "vim +%l %f"   # %f = file path, %l = line number
    editor-terminal: "tmux"    # tmux | iterm2 | terminal | "" (empty = run cmd directly)
    editor-sock: "~/.local/share/rtl-buddy/wave-nvim.sock"  # optional: nvim remote reuse
    ctrl-sock: "~/.local/share/rtl-buddy/wave-ctrl.sock"    # optional: nvim → Surfer

cfg-synth-tools:
  - name: "yosys"
    tool: "yosys"
    opts:
      synth-args: ""
      abc-args: ""
      frontend: "verilog"              # "verilog" (default) | "slang"
      plugin-path: ""                  # required if frontend: slang — path to slang.so
  - name: "openroad"
    tool: "openroad"
    opts:
      strategy: "AREA"   # AREA | TIMING | TIMING_ANNEAL | TIMING_GENETIC
      frontend: "verilog"
      plugin-path: ""

cfg-pdks:
  - name: "sky130hd"
    site: "unithd"
    corners:
      tt: "pdk/sky130hd/lib/sky130_fd_sc_hd__tt_025C_1v80.lib"
    tech-lef:  "pdk/sky130hd/lef/sky130_fd_sc_hd.tlef"
    macro-lef: "pdk/sky130hd/lef/sky130_fd_sc_hd_merged.lef"
    cell-gds:      "pdk/sky130hd/gds/sky130_fd_sc_hd.gds"
    klayout-tech:  "pdk/sky130hd/sky130hd.lyt"
    klayout-props: "pdk/sky130hd/sky130hd.lyp"
    tie-hi: "sky130_fd_sc_hd__conb_1/HI"
    tie-lo: "sky130_fd_sc_hd__conb_1/LO"
    fill-cells: [sky130_fd_sc_hd__fill_1, sky130_fd_sc_hd__fill_2]

cfg-synth-platforms:
  - name: "sky130hd_tt"
    pdk: "sky130hd"
    corner: "tt"

cfg-pnr-platforms:
  - name: "sky130hd_tt"
    pdk: "sky130hd"
    corner: "tt"
    cts-buffer: "sky130_fd_sc_hd__clkbuf_4"
    routing-layers:
      signal: "met1-met5"
      clock:  "met3-met5"

cfg-synth-efforts:
  - name: "quick"
    yosys:
      synth-args: "-flatten"
      abc-args: "-fast"
    openroad:
      run: false               # skip OpenROAD entirely → Yosys-only fast path
  - name: "standard"
    openroad:
      run: true                # current default behaviour: STA with ideal wires
  - name: "accurate"
    openroad:
      run: true
      pre-sta-tcl: |
        initialize_floorplan -utilization 0.7 -aspect_ratio 1.0 \
          -core_space 2.0 -site unithd
        global_placement -density 0.7
        estimate_parasitics -placement

cfg-pnr-tools:
  - name: "openroad"
    tool: "openroad"            # bare name → found via PATH; or absolute path

cfg-cdc-tools:
  - name: "rtl-buddy-cdc"
    tool: "rtl-buddy-cdc"
    opts:
      sync-depth: 2          # forwarded as `--sync-depth N` (CDC-002 required depth)
      extra-args: ""         # appended verbatim to every invocation

cfg-fpv-tools:
  - name: "sby"
    tool: "sby"              # bare name → found via PATH; or absolute path
    opts:
      timeout: 600           # per-task timeout in seconds; written to sby [options]
      extra-args: ""         # appended verbatim to every sby invocation
      solver-versions:       # optional pins; map solver name → exact version
        yices: "2.6.4"       # known names: yices, z3, boolector, bitwuzla,
        z3: "4.13.0"         # btormc, abc. Hard-fails on mismatch.

cfg-rtl-reg:
  reg-cfg-path: "design/regression.yaml"

Runtime effects:

Platform is selected by matching uname output against cfg-platforms[].unames.
--builder overrides the platform-selected builder for the current run.
--builder-mode selects which named builder-opts entry to use for compile-time and run-time flags.
cfg-coverage is keyed by simulator family (e.g. verilator). use-lcov: true enables .info export and LCOV HTML generation when --coverage-html is used.
cfg-coverview is keyed by simulator family. generate-tables sets the coverage type for Coverview tables. config is a dict of inline Coverview JSON configuration values.
cfg-surfer configures the Surfer waveform viewer used by rb wave. path is a bare executable name (resolved via PATH) or a relative/absolute path to the binary. editor-cmd supports %f (file path) and %l (line number) placeholders. editor-terminal controls how the editor is launched: tmux opens a new tmux window, iterm2 and terminal use AppleScript, empty string runs the command directly (suitable for GUI editors like VS Code). editor-sock is an optional Unix socket path that enables nvim remote reuse: rtl-buddy launches nvim with --listen <sock> on first use and reconnects for subsequent events. ctrl-sock is an optional Unix socket for the wave control server, which lets nvim send signals to Surfer — press <Space>wa (or your <leader>wa) on a signal name to add it to the waveform view. Install the bundled nvim plugin first with rb wave-install-nvim.
cfg-synth-tools defines synthesis tool entries selected by synth.yaml tool fields. tool is the path to the executable, or a bare name if it is available on PATH. For the Yosys backend, opts.synth-args are appended to the synth command and opts.abc-args are used by the unmapped ABC step. For the OpenROAD backend, opts.strategy controls optional resynthesis (AREA = none, TIMING/TIMING_ANNEAL = resynth_annealing, TIMING_GENETIC = resynth_genetic). opts.frontend selects the SystemVerilog parser: "verilog" (default) uses Yosys's built-in read_verilog -sv -defer per source — fast, lazy elaboration, but a small SV subset. "slang" loads the yosys-slang plugin and calls read_slang instead — full SV-2017 (package imports, packed-struct typedefs, complex generates) with eager elaboration. opts.plugin-path is required when frontend: slang; absolute paths pass through and relative paths resolve against the project root. Both options accept per-block overrides via synth.yaml tool_overrides.yosys.frontend / .plugin_path (note: tool_overrides keys are snake_case Python attribute names, while cfg-synth-tools.opts uses kebab-case YAML — same field, two names, see synthesis concept doc for the convention). The override key is always yosys (the elaboration tool), regardless of whether the synth selects tool: yosys or tool: openroad. The OpenROAD backend runs Yosys for elaboration → write_verilog → OpenROAD reads the netlist, so its elaboration-stage opts come from the yosys tool config + tool_overrides.yosys block.
cfg-pdks defines one entry per process. Each holds all PDK-bound assets — Liberty per corner (under corners:), tech-lef / macro-lef, optional cell-gds, KLayout .lyt / .lyp for streamout, SITE, and tie-hi / tie-lo / fill-cells for P&R. Paths are resolved relative to root_config.yaml. Multiple PDKs can coexist; downstream platform blocks select which one to use.
cfg-synth-platforms selects a cfg-pdks entry + corner for synthesis. Each entry has name (referenced by platform: in synth.yaml), pdk (PDK entry name), and corner (optional — defaults to the first declared corner). Block-specific LEFs go on the synth.yaml entry (lef-paths:) on top of the PDK's tech/macro LEFs.
cfg-pnr-platforms selects a cfg-pdks entry + STA corner for place-and-route. Each entry has name (referenced by platform: in pnr.yaml), pdk, optional corner (defaults to first corner), cts-buffer (clock-tree buffer cell), and routing-layers with signal / clock layer ranges.
cfg-synth-efforts defines named synthesis effort levels referenced by synth.yaml effort fields or the --effort CLI flag. Each entry has optional yosys.synth-args / yosys.abc-args (merged into the Yosys stage) and an openroad block. When openroad.run: false, the runner falls back to the Yosys-only backend even if tool: openroad was selected — useful for a fast quick-look path that needs no LEF/STA. openroad.pre-sta-tcl is a raw Tcl snippet injected into synth.tcl between read_sdc and report_checks; use it to insert floorplan/placement/parasitic-estimation steps before timing analysis. When no cfg-synth-efforts entries are configured or no effort is selected, a built-in standard effort with all defaults is used. Precedence for the same knob: per-synthesis tool_overrides > cfg-synth-efforts > cfg-synth-tools.
cfg-pnr-tools defines P&R tool entries selected by pnr.yaml tool fields. tool is the path to the executable, or a bare name if it is available on PATH. When pnr.yaml tool does not match a cfg-pnr-tools entry, the value is used as the executable name directly (bare-name on PATH semantics).
cfg-cdc-tools defines CDC tool entries selected by cdc.yaml tool fields. tool is the path to the executable, or a bare name if it is available on PATH. opts.sync-depth is forwarded as --sync-depth N and controls CDC-002's required synchronizer depth. opts.extra-args is appended verbatim to every analyzer invocation.
cfg-fpv-tools defines FPV tool entries selected by fpv.yaml tool fields. tool is the path to the executable, or a bare name if it is available on PATH. opts.timeout is written to the generated .sby [options] block as a per-task timeout in seconds. opts.extra-args is appended verbatim to every sby invocation. opts.solver-versions is an optional map of solver short name → exact version string (e.g. yices: "2.6.4"); known solvers are yices, z3, boolector, bitwuzla, btormc, abc. Each pinned solver is probed before every run and the run hard-fails with a single multi-line summary if any version does not match — protects CI reproducibility against drift in locally-installed solvers.
cfg-rtl-reg.reg-cfg-path is the fallback regression file for rtl-buddy regression when no ./regression.yaml exists in the cwd.
cfg-verible[].path is the directory containing Verible executables. Absolute paths are used as-is; relative paths are resolved from the directory containing root_config.yaml.

regression.yaml

Required keys:

rtl-buddy-filetype: reg_config
test-configs

Example:

rtl-buddy-filetype: reg_config

test-configs:
  - "design/example_block_a/verif/tests.yaml"
  - "design/example_block_b/verif/tests.yaml"

Runtime effects:

rtl-buddy regression iterates each listed suite and runs tests filtered by --start-level/--reg-level.
regression changes directory into each suite directory before running.

models.yaml

Required keys:

rtl-buddy-filetype: model_config
models

Example:

rtl-buddy-filetype: model_config

models:
  - name: "my_design"
    desc: "Optional human-readable description"
    filelist:
      - "-F my_design.f"
    spec: "../../spec/my_design/specs.yaml"
    cdc:   "../../cdc/my_design/cdc.yaml"
    synth: "../../synth/my_design/synth.yaml#fast"
    tests: "../../verif/my_design/tests.yaml"

Optional fields:

Field	Type	Description
`desc`	string	Human-readable model description
`spec`	string	Path to the block's `specs.yaml`, relative to this `models.yaml` file. Used by `rb spec check-design` to link the design model to its specification.
`cdc`	string	Path to the `cdc.yaml` that owns this model's CDC analysis, relative to this `models.yaml`. Optional `#analysis_name` fragment picks one analysis from a multi-analysis file (e.g. `cdc.yaml#full_design`). Read by `rb hub` to enable the clock-domain overlay; absent → overlay unavailable.
`synth`	string	Path to the `synth.yaml` that owns this model's synthesis flow, relative to this `models.yaml`. Same `#synth_name` fragment semantics. Declared now for forward compatibility; no consumer reads it yet.
`tests`	string	Path to the `tests.yaml` that owns this model's testbench/test suite, relative to this `models.yaml`. Same `#test_name` fragment semantics. Declared now for forward compatibility; no consumer reads it yet.

Runtime effects:

tests.yaml references a model by name using the model and model_path fields.
Model filelists are parsed by the filelist logic: -F recursion, +incdir+, +libext+, -v, -y, and plain source paths are all supported.
spec is not used at simulation time; it is only consumed by the rb spec traceability commands.
cdc / synth / tests are back-pointers — the downstream files still carry their own model: + model_path: references back to this one. The model-side entry is the source of truth for "which analysis owns this model" when there could otherwise be ambiguity (e.g. two cdc.yaml files reference the same model name).

tests.yaml

Required keys:

rtl-buddy-filetype: test_config
testbenches
tests

Example:

rtl-buddy-filetype: test_config

testbenches:
  - name: "tb_top"
    filelist:
      - "+incdir+../../../verif/tb"
      - "tb_top.sv"

tests:
  - name: "smoke"
    desc: "sanity test"
    reglvl: 0
    model: "my_design"
    model_path: "../src/models.yaml"
    testbench: "tb_top"
    plusargs:
      test_cycles: "50"
      lvm_verbosity: 1
    plusdefines:
      FEATURE_X: "1"
    sim_timeout: 120
    uvm:
      max_warns: 0
      max_errors: 0

  - name: "sweep_case"
    desc: "expands to many tests"
    reglvl:
      default: 2000
      vcs: 3000
    model: "my_design"
    model_path: "../src/models.yaml"
    testbench: "tb_top"
    sweep:
      path: "example_sweep.py"

Field reference:

Field	Type	Description
`name`	string	Test identifier; used in log file names
`desc`	string	Human-readable description
`reglvl`	int or dict	Regression level; int for all builders, dict for per-builder with `default`
`model`	string	Model name from `models.yaml`
`model_path`	string	Path to `models.yaml`; resolved relative to the suite directory
`testbench`	string	Testbench name from `testbenches` list
`plusargs`	dict	`KEY: VALUE` → `+KEY=VALUE` at sim runtime
`plusdefines`	dict	`KEY: VALUE` → `+define+KEY=VALUE` at compile time
`sim_timeout`	int	Timeout in seconds (default: 60)
`uvm.max_warns`	int	UVM warning threshold; exceeding it fails the test
`uvm.max_errors`	int	UVM error threshold; exceeding it fails the test
`sweep.path`	string	Path to sweep expansion script
`preproc.path`	string	Path to pre-processing script
`postproc.path`	string	Path to post-processing script (parsed but not yet fully active)
`covers`	list of strings	IDs of spec coverage items this test addresses (e.g. `["BLOCK-COV-01"]`). Used by `rb spec check-coverage`; has no effect at simulation time.

cocotb testbenches

Adding a cocotb: block to a testbench entry switches the runner to cocotb/VPI mode (Verilator only for now). toplevel: is required when cocotb: is present; omitting it raises a fatal error at config-load time.

Prerequisite: cocotb must be installed in the active Python environment (uv add cocotb or pip install cocotb). The runner invokes cocotb-config at compile time; a missing binary surfaces as a FatalRtlBuddyError with an actionable message.

testbenches:
  - name: "tb_my_design"
    filelist:
      - "my_design.sv"
    toplevel: my_design          # DUT top-level module name — required for cocotb
    cocotb:
      module: test_my_design     # Python module(s) containing @cocotb.test() coroutines

  - name: "tb_multi"
    filelist:
      - "my_design.sv"
    toplevel: my_design
    cocotb:
      module:                    # list form: all modules are loaded
        - test_smoke
        - test_corner_cases

Pass/fail detection for cocotb testbenches:

cocotb writes a JUnit XML results file (cocotb_results.xml) instead of PASS/FAIL stdout lines. rtl_buddy parses this file automatically after simulation; you do not need $display("PASS …") in cocotb tests. The desc field in the result reports the first three failure messages and a (+N more) suffix when there are more.

Testbench field reference (cocotb-specific additions):

Field	Type	Required	Description
`toplevel`	string	Yes (cocotb only)	Top-level DUT module name passed to `COCOTB_TOPLEVEL`
`cocotb.module`	string or list	Yes	Python test module(s) passed to `COCOTB_TEST_MODULES`

Runtime effects by field:

testbench: selects entry from testbenches; its filelist is appended to model sources for compilation.
model_path: resolved relative to the tests.yaml file's directory.
reglvl as dict: use default as the fallback for builders not listed.
plusdefines: converted to +define+KEY (no value) or +define+KEY=VALUE.
plusargs: converted to +KEY (no value) or +KEY=VALUE.
sim_timeout: applies per test run, not per iteration in randtest.
sweep.path: Python script that expands one test entry into a list of TestConfig objects. See Plugins.
preproc.path: Python script executed before compile; can mutate test_cfg and root_cfg, and receives suite_dir plus artifact_dir in its execution namespace. See Plugins.

Path semantics and cwd

rtl_buddy.log and the convenience symlinks (test.log, test.err, test.randseed) are written to the suite root (the current working directory).
Per-test artifacts are written to artefacts/{test_name}/ under the suite root. Single runs write test.log, test.err, test.randseed, compile.log, run.f, and (if enabled) coverage.dat there directly. Repeated runs (randtest) write sim outputs into numbered subdirectories: artefacts/{test_name}/run-0001/, etc.
test and randtest do not automatically change into the suite directory. Run from the suite directory, or use --test-config with a full path.
regression does chdir into each suite directory before executing.
Preproc plusargs are passed to the simulator verbatim. Resolve suite-local input paths explicitly against suite_dir; keep output filenames artifact-relative when they should land under artefacts/{test_name}/.
For portable configs in multi-suite repos, make paths in tests.yaml explicit and verify they resolve correctly from the intended invocation directory.

synth.yaml

Required keys:

rtl-buddy-filetype: synth_config
syntheses

Example:

rtl-buddy-filetype: synth_config

syntheses:
  - name: "smoke_synth"
    desc: "Synthesize my_design with the default Yosys flow"
    model: "my_design"
    model_path: "../src/models.yaml"
    tool: "yosys"
    reglvl: 0

  - name: "sky130_synth"
    desc: "Technology-mapped synthesis for SKY130 (Yosys)"
    model: "my_design"
    model_path: "../src/models.yaml"
    tool: "yosys"
    constraints: "constraints.sdc"
    platform: "sky130hd_tt"
    params:
      WIDTH: 32
    defines:
      TARGET_SYNTH: 1
    reglvl:
      default: 0
      dc: 1000
    tool_overrides:
      yosys:
        synth_args: "-flatten"

  - name: "sky130_openroad"
    desc: "Technology-mapped synthesis with OpenROAD timing analysis"
    model: "my_design"
    model_path: "../src/models.yaml"
    tool: "openroad"
    constraints: "constraints.sdc"
    platform: "sky130hd_tt"
    effort: "accurate"     # references cfg-synth-efforts entry; overridable via --effort
    reglvl: 0

Field reference:

Field	Type	Description
`name`	string	Synthesis identifier; used on the CLI and in `artefacts/{name}/`
`desc`	string	Human-readable synthesis description
`model`	string	Model name from `models.yaml`; also used as the Yosys top module
`model_path`	string	Path to `models.yaml`, resolved relative to the `synth.yaml` file
`tool`	string	Synthesis tool name from `root_config.yaml` `cfg-synth-tools`
`constraints`	string	Optional SDC file path, resolved relative to the `synth.yaml` file
`params`	dict	Optional top-level parameter overrides passed through Yosys `chparam -set`
`defines`	dict	Optional Verilog defines passed to `read_verilog` as `-D KEY=VALUE`
`platform`	string	Optional `cfg-synth-platforms` name (which references a `cfg-pdks` entry); enables technology mapping
`lef-paths`	list of strings	Optional block-specific LEF files (paths resolved relative to the `synth.yaml` file); appended after the PDK's tech/macro LEFs for the OpenROAD backend
`reglvl`	int or dict	Regression level; int for all tools, dict for per-tool with `default`
`tool_overrides`	dict	Optional per-tool overrides for `synth_args`, `abc_args`, or `strategy`, keyed by synthesis tool name
`effort`	string	Optional effort name from `cfg-synth-efforts`; controls Yosys synth/abc args and OpenROAD `pre-sta-tcl`. Overridable per invocation with `rtl-buddy synth --effort <name>`. Omitted ⇒ built-in `standard` defaults.

Runtime effects:

rtl-buddy synth loads synth.yaml, resolves sources via models.yaml, and dispatches to the backend selected by tool.
Yosys backend (tool: "yosys"): writes synth.f and synth.ys, runs Yosys, captures output in synth.log. Without platform, emits RTLIL; with platform, runs dfflibmap + abc -liberty and emits synth_netlist.v. Reports Gates, Area (lib-mapped only), and WNS (lib-mapped with SDC). Passes when exit code is 0 and synth.log has no ERROR: lines.
OpenROAD backend (tool: "openroad"): requires platform pointing at a cfg-synth-platforms entry whose PDK has tech-lef / macro-lef set. Stage 1 runs Yosys to produce synth_netlist.v (logged to synth_yosys.log). Stage 2 runs OpenROAD with synth.tcl which calls read_lef, read_liberty, read_verilog, link_design, read_sdc (native multi-clock), and reports area/timing; output in synth.log. Reports Gates, Area, WNS (from report_checks -path_delay max), and TNS (from report_tns). Passes when both stages exit with code 0 and neither log contains errors.
If constraints contains create_clock entries, the Yosys backend uses the minimum period as ABC's -D constraint (multi-clock workaround). The OpenROAD backend passes the full SDC to read_sdc without modification.
effort selects an entry from root_config.yaml cfg-synth-efforts. If the selected effort has openroad.run: false, a synthesis with tool: openroad falls back to the Yosys-only backend (no LEF/STA required) — this is the recommended "quick" path for iteration. The --effort CLI flag on rtl-buddy synth and rtl-buddy synth-regression overrides whatever is set per-synthesis.

synth_regression.yaml

Required keys:

rtl-buddy-filetype: synth_reg_config
synth-configs

Example:

rtl-buddy-filetype: synth_reg_config

synth-configs:
  - "design/example_block_a/synth/synth.yaml"
  - "design/example_block_b/synth/synth.yaml"

Runtime effects:

rtl-buddy synth-regression iterates each listed synth.yaml file and filters syntheses by --reg-level.
Paths in synth-configs are resolved relative to the synth_regression.yaml file.
synth-regression changes directory into each synthesis suite directory before executing its entries.

pnr.yaml

Required keys:

rtl-buddy-filetype: pnr_config
runs

Example:

rtl-buddy-filetype: pnr_config

runs:
  - name: "demo_pnr_nangate45"
    desc: "OpenROAD P&R on Nangate45 typ corner"
    tool: "openroad"
    synth: "demo_synth_nangate45"
    synth-path: "../../synth/demo/synth.yaml"
    constraints: "../../synth/demo/constraints.sdc"
    platform: "nangate45_typ"
    floorplan:
      utilization: 0.55
      aspect: 1.0
      core-margin: 2.0
    reglvl: 1000

Field reference:

Field	Type	Description
`name`	string	P&R run identifier; used on the CLI and in `artefacts/<name>/`
`desc`	string	Human-readable description
`tool`	string	Backend tool — `"openroad"` is the only supported value today
`synth`	string	Name of the upstream `rb synth` entry that produced the netlist
`synth-path`	string	Path to the `synth.yaml` that defines `synth`, resolved relative to `pnr.yaml`
`constraints`	string	Path to the SDC file (required), resolved relative to `pnr.yaml`
`platform`	string	`cfg-pnr-platforms` entry name
`floorplan.utilization`	float	Core utilization (0–1)
`floorplan.aspect`	float	Die aspect ratio
`floorplan.core-margin`	float	Margin between core area and die edge, in microns
`reglvl`	int or dict	Regression level for filtering; same semantics as `synth.yaml` reglvl (int for all tools, dict for per-tool with `default`)
`tool_overrides`	dict	Reserved for tool-specific overrides (none consumed today)

Runtime effects:

rb pnr loads pnr.yaml, resolves the upstream synth-path + synth to find <synth_dir>/artefacts/<synth_name>/synth_netlist.v, and dispatches to the OpenROAD backend.
The backend writes pnr.tcl from a bundled template, invokes openroad -no_init -exit -log artefacts/<name>/pnr.log artefacts/<name>/pnr.tcl, and produces routed DEF + post-route netlist/SDC + timing/DRC reports under artefacts/<name>/.
The selected cfg-pnr-platforms entry provides Liberty, tech-LEF, macro-LEF, SITE, tie cells, fill cells, CTS buffer, and routing layer ranges via its referenced cfg-pdks entry.
Pass when OpenROAD exits 0 and the log has no [ERROR ...] lines. SKIP when the entry's reglvl is above --reg-level or tool: is not openroad.

cdc.yaml

Required keys:

rtl-buddy-filetype: cdc_config
analyses

Example:

rtl-buddy-filetype: cdc_config

analyses:
  - name: "ip_cdc_handshake_lint"
    desc: "CDC lint of the request/ack handshake IP"
    model: "ip_cdc_handshake"
    model_path: "../../design/common/models.yaml"
    tool: "rtl-buddy-cdc"
    constraints: "ip_cdc_handshake.sdc"
    waivers: "ip_cdc_handshake.waivers"   # optional
    reglvl: 0

  - name: "alu_accel_lint"
    desc: "CDC lint of the ALU accelerator"
    model: "alu_accel_top"
    model_path: "../../design/alu_accel/models.yaml"
    tool: "rtl-buddy-cdc"
    constraints: "alu_accel_top.sdc"
    frontend: "slang"   # opt this analysis into the slang elaboration frontend
    reglvl:
      default: 0
      rtl-buddy-cdc: 100
    tool_overrides:
      rtl-buddy-cdc:
        sync_depth: 3
        extra_args: "--strict"

Field reference:

Field	Type	Description
`name`	string	Analysis identifier; used on the CLI and in `artefacts/{name}/`
`desc`	string	Human-readable analysis description
`model`	string	Model name from `models.yaml`; also used as the top module for elaboration
`model_path`	string	Path to `models.yaml`, resolved relative to the `cdc.yaml` file
`tool`	string	CDC tool name from `root_config.yaml` `cfg-cdc-tools`
`constraints`	string	SDC file path, resolved relative to the `cdc.yaml` file
`waivers`	string	Optional waiver file path, resolved relative to the `cdc.yaml` file
`reglvl`	int or dict	Regression level; int for all tools, dict for per-tool with `default`
`tool_overrides`	dict	Optional per-tool overrides for `sync_depth` or `extra_args`, keyed by CDC tool name
`frontend`	string	Optional elaboration frontend selector forwarded as-is via `--frontend <value>` to the analyzer subprocess. The set of accepted values is the analyzer's, not rtl_buddy's — for the bundled `rtl-buddy-cdc` backend on current main it's `"yosys"` (built-in) or `"slang"` (full SV-2017 via the optional `pyslang`-backed `[slang]` extra); see the analyzer's own docs for the authoritative list. Unknown values are rejected by the analyzer, not by rtl_buddy. Omit to use the analyzer's own default.

Runtime effects:

rtl-buddy cdc loads cdc.yaml, resolves sources via models.yaml, and dispatches to the backend selected by tool.
The bundled rtl-buddy-cdc backend invokes the standalone rtl-buddy-cdc lint CLI as a subprocess. The analysis receives the model's resolved filelist, the SDC, an optional waivers file, the merged tool opts (root cfg-cdc-tools baseline plus any matching tool_overrides.<tool>), and — when set — --frontend <value> from the per-analysis frontend field.
frontend is per-analysis (not on cfg-cdc-tools opts) — different from the synth side, where the equivalent selector lives on cfg-synth-tools.opts.frontend. Per-analysis suits the CDC use case because slang-required and Yosys-only analyses commonly coexist in one suite, and there is no useful project-wide default.
Each analysis writes a text report and a machine-readable JSON report under artefacts/{name}/; the JSON summary is parsed to populate the pass/fail/skip result for the CLI table.
rtl-buddy cdc <name> --list lists configured analyses without running them.

cdc_regression.yaml

Required keys:

rtl-buddy-filetype: cdc_reg_config
cdc-configs

Example:

rtl-buddy-filetype: cdc_reg_config

cdc-configs:
  - "design/example_block_a/lint/cdc.yaml"
  - "design/example_block_b/lint/cdc.yaml"

Runtime effects:

rtl-buddy cdc-regression iterates each listed cdc.yaml file and filters analyses by --reg-level.
Paths in cdc-configs are resolved relative to the cdc_regression.yaml file.
cdc-regression changes directory into each CDC suite directory before executing its entries.

fpv.yaml

Required keys:

rtl-buddy-filetype: fpv_config
verifications

Example:

rtl-buddy-filetype: fpv_config

verifications:
  - name: "demo_fpv_fifo"
    desc: "Bounded proof of FIFO interface assertions"
    tool: "sby"
    model: "demo_fifo"
    model_path: "../../design/demo_fifo/models.yaml"
    top: "demo_fifo"
    constraints: "shared_clock_reset.sv"   # optional environment assumes
    properties:
      - "demo_fifo_props.sv"
    mode: "bmc"
    depth: 32
    engines:
      - "smtbmc yices"
    reglvl: 1000

  - name: "alu_accel_fpv"
    desc: "k-induction prove of ALU accelerator invariants"
    tool: "sby"
    model: "alu_accel_top"
    model_path: "../../design/alu_accel/models.yaml"
    properties:
      - "alu_accel_props.sv"
    mode: "prove"
    depth: 16
    engines:
      - "smtbmc z3"
      - "abc pdr"
    reglvl:
      default: 0
      sby: 1000
    tool_overrides:
      sby:
        timeout: 1800
        extra_args: ""

Field reference:

Field	Type	Description
`name`	string	Verification identifier; used on the CLI and in `artefacts/{name}/`
`desc`	string	Human-readable verification description
`tool`	string	FPV tool name from `root_config.yaml` `cfg-fpv-tools`
`model`	string	Model name from `models.yaml`
`model_path`	string	Path to `models.yaml`, resolved relative to the `fpv.yaml` file
`top`	string	Top module name passed to `prep -top`; defaults to `model`
`properties`	list	SystemVerilog files containing SVA properties / bound checkers, resolved relative to `fpv.yaml`. Optional when properties are in-RTL under `ifdef FORMAL guards
`constraints`	string	Optional path to a single `.sv` file with environment `assume property` statements (clock toggle, reset sequence, etc.). Read into the sby script before `properties:` so the assumes are in scope when asserts elaborate. Resolved relative to `fpv.yaml`. Analogous to `constraints:` in `pnr.yaml` — separates "environment" from "what to prove" and lets multiple verifications share one clock/reset boilerplate.
`mode`	string	One of `bmc`, `prove`, `cover`, `live`; defaults to `bmc`
`depth`	int	Cycle depth for the proof; defaults to 20
`engines`	list	Sby engine specs (e.g. `smtbmc yices`, `abc pdr`); defaults to `["smtbmc yices"]`
`reglvl`	int or dict	Regression level; int for all tools, dict for per-tool with `default`
`tool_overrides`	dict	Optional per-tool overrides for `timeout` or `extra_args`, keyed by FPV tool name

Runtime effects:

rtl-buddy fpv loads fpv.yaml, resolves the model's filelist via models.yaml, and dispatches to the backend selected by tool.
The bundled sby backend generates a .sby config containing [options] (mode, depth, optional timeout), [engines], [script] (Yosys read + prep), and [files] (resolved source paths), then invokes sby -f -d <workdir> <config>.
Each verification writes the generated config, the full sby log, and the sby workdir under artefacts/{name}/; the workdir's status file is the authoritative pass/fail signal, with the process exit code as fallback.
Counterexample VCDs (on FAIL) land at artefacts/{name}/sby_workdir/engine_<N>/trace.vcd.
rtl-buddy fpv <name> --list lists configured verifications without running them.

fpv_regression.yaml

Required keys:

rtl-buddy-filetype: fpv_reg_config
fpv-configs

Example:

rtl-buddy-filetype: fpv_reg_config

fpv-configs:
  - "design/example_block_a/fpv/fpv.yaml"
  - "design/example_block_b/fpv/fpv.yaml"

Runtime effects:

rtl-buddy fpv-regression iterates each listed fpv.yaml file and filters verifications by --reg-level.
Paths in fpv-configs are resolved relative to the fpv_regression.yaml file.
fpv-regression changes directory into each FPV suite directory before executing its entries.

specs.yaml

specs.yaml lives in spec/<block>/ and defines the functional specification for one or more design blocks. It is consumed by the rb spec traceability commands and has no effect on simulation.

Required keys:

rtl-buddy-filetype: spec_config
blocks

Example:

rtl-buddy-filetype: spec_config

blocks:
  - name: "my_design"
    desc: "Brief description of the block"
    docs:
      - "README.md"
      - "behavior.md"
    coverage-items:
      - id: "MY-COV-01"
        desc: "Normal operation path"
      - id: "MY-COV-02"
        desc: "Error handling and recovery"

Block field reference:

Field	Type	Description
`name`	string	Block identifier; matched against `ModelConfig.name` when resolving `spec:` links in `models.yaml`. For single-block files the name is matched unconditionally.
`desc`	string	Human-readable block description
`docs`	list of strings	Paths to markdown spec documents, relative to this `specs.yaml` file
`coverage-items`	list	Functional coverage items for this block

Coverage item fields:

Field	Type	Description
`id`	string	Unique coverage item identifier, referenced by `covers` in `tests.yaml`
`desc`	string	Human-readable description of what must be tested

See Spec Traceability for the end-to-end workflow.

Authoring checklist for new suites

Add or verify the model entry in models.yaml.
Add a testbench entry and verify the filelist paths resolve correctly.
Add at least one test entry with model, model_path, and testbench.
Set reglvl policy: 0 for must-run sanity tests, larger values for extended tests.
Add the suite path to regression.yaml.

Run a smoke pass:

rtl-buddy --machine test <name> -c <suite>/tests.yaml
rtl-buddy --machine regression -c <regression.yaml> -s 0 -l 0

root_config.yaml​

regression.yaml​

models.yaml​

tests.yaml​

cocotb testbenches​

Path semantics and cwd​

synth.yaml​

synth_regression.yaml​

pnr.yaml​

cdc.yaml​

cdc_regression.yaml​

fpv.yaml​

fpv_regression.yaml​

specs.yaml​

Authoring checklist for new suites​

root_config.yaml

regression.yaml

models.yaml

tests.yaml

cocotb testbenches

Path semantics and cwd

synth.yaml

synth_regression.yaml

pnr.yaml

cdc.yaml

cdc_regression.yaml

fpv.yaml

fpv_regression.yaml

specs.yaml

Authoring checklist for new suites