pharaoh-feat-component-extract

name	pharaoh-feat-component-extract
description	Use when reverse-engineering a feat and you need to derive a component composition diagram automatically from the feat + its source files. Walks import edges between the listed files and emits a Mermaid or PlantUML diagram whose output shape is compatible with pharaoh-component-diagram-draft. Does NOT hand-author nodes or edges; extraction is rule-based.

pharaoh-feat-component-extract

When to use

Invoke after pharaoh-feat-file-map has produced a {feat_id, files} mapping, when you want a static architecture view of the feature showing which modules/classes compose it and how they depend on each other. The diagram output shape matches pharaoh-component-diagram-draft so downstream tooling (sphinx-needs rendering, diff review) treats auto-extracted diagrams identically to hand-authored ones.

Do NOT use to draft a diagram from scratch when you already have explicit node+edge data — that is pharaoh-component-diagram-draft. Do NOT use to extract runtime flow — that is pharaoh-feat-flow-extract.

Tailoring awareness

Shared tailoring rules: see shared/diagram-tailoring.md. Reads [pharaoh.diagrams] and [pharaoh.diagrams.component] from the consumer project's pharaoh.toml for renderer choice and styling. Respects on_missing_config per the shared check → propose → confirm pattern.

Safe-label rules: see shared/diagram-safe-labels.md. Node IDs derived from file paths MUST be aliased (path characters / and . are invalid in Mermaid / PlantUML identifier positions). Edge labels MUST be sanitised — call-labels like foo(arg1; arg2) become foo(arg1, arg2) before emit. A parse failure in the emitted block is invisible under sphinx-build and surfaces only at browser render time; pharaoh-diagram-lint (run as part of pharaoh-quality-gate) is the second guard.

Atomicity

• (a) Indivisible — one feat + one file list in → one diagram RST block out. No multi-feat bundling. No mutation of source files. No req emission.

• (b) Input: {feat_id: str, feat_title: str, files: list[str], project_root: str, src_root: str, renderer_override?: "mermaid"|"plantuml", include_external?: bool, on_missing_config?: "fail"|"prompt"|"use_default", papyrus_workspace?: str, reporter_id: str}. Output: one RST directive block (.. mermaid:: or .. uml::) with caption <feat_id> — component composition. No surrounding prose.

• (c) Reward: fixture pharaoh-validation/fixtures/pharaoh-feat-component-extract/:

  • input_feat.yaml declares feat_id: FEAT_csv_export, feat_title: "CSV Export", files: [csv/export.py, csv/writer.py, commands/csv.py].
  • input_files/ contains three Python files with explicit imports: commands/csv.py imports from csv.export import run_export; csv/export.py imports from csv.writer import CSVWriter; csv/writer.py has no project-internal imports.
  • Expected diagram at expected_diagram.rst has 3 nodes (one per file), 2 directed edges (commands/csv.py → csv/export.py, csv/export.py → csv/writer.py), no external nodes.

  Scorer:

  1. Output starts with the renderer directive.
  2. All 3 nodes appear by label.
  3. Both directed edges render with correct arrow syntax.
  4. With default include_external=false, no external imports (e.g. typer, pathlib, csv) appear as nodes.
  5. With include_external=true, external imports render as ghost nodes (dashed outline, muted color, <<external>> stereotype).
  6. Output matches pharaoh-component-diagram-draft output shape (same directive, same caption format, same node/edge syntax).

  Pass = all 6.

• (d) Reusable for any language whose import graph the extractor supports. Python initial target; regex-based import detection so adding Rust/TypeScript is a configuration table entry, not a rewrite.

• (e) Composable: one feat per call. A plan emitted by pharaoh-write-plan may include a foreach task over feats that dispatches N instances (one per feat) in parallel via pharaoh-execute-plan. This skill never invokes other skills.

Input

• feat_id: the feature's sphinx-needs ID, used as the diagram caption prefix.
• feat_title: human-readable title, shown in caption.
• files: list of source file paths relative to src_root. These become the diagram's in-scope nodes.
• project_root: absolute path, for pharaoh.toml tailoring lookup.
• src_root: absolute path, the import-graph resolution root. files[*] resolve as <src_root>/<file>.
• renderer_override (optional): per shared doc.
• include_external (optional): if true, imports that resolve outside files but inside src_root become ghost nodes. Imports resolving outside src_root entirely (stdlib, third-party) are ignored regardless. Default false.
• on_missing_config (optional): per shared doc. Default "prompt".
• papyrus_workspace (optional): for consistent node labeling with other skills that reference the same files.
• reporter_id: short agent identifier.

Output

Mermaid (default):

.. mermaid::
   :caption: FEAT_csv_export — component composition

   graph TD
       commands_csv[commands/csv.py<br/>run_export]
       csv_export[csv/export.py<br/>run_export]
       csv_writer[csv/writer.py<br/>CSVWriter]
       commands_csv --> csv_export
       csv_export --> csv_writer

Node IDs (left-hand side of the bracket) are sanitized forms of the file path (replace / and . with _). Node labels show the file path plus the primary symbol (largest top-level def/class, or the one whose name matches feat title tokens).

PlantUML:

.. uml::
   :caption: FEAT_csv_export — component composition

   @startuml
   component "commands/csv.py\n(run_export)" as commands_csv
   component "csv/export.py\n(run_export)" as csv_export
   component "csv/writer.py\n(CSVWriter)" as csv_writer
   commands_csv --> csv_export
   csv_export --> csv_writer
   @enduml

Process

Step 1: Enumerate nodes

For each file in files, read via absolute path (<src_root>/<file>). Parse top-level symbol declarations:

• Python: ^class <Name>, ^def <Name>, ^async def <Name>.
• Rust: ^(pub )?(fn|struct|enum|trait|impl) <Name>.
• JS/TS: ^(export )?(function|class|const|let|var) <Name>.
• Go: ^func (<Receiver>) <Name> / ^type <Name>.

Pick the primary symbol per file: longest body OR name matching feat_title tokens (case-insensitive substring match on any token). If ambiguous, pick the one defined earliest.

Node label: <file>\n(<primary_symbol>) (Mermaid uses <br/>, PlantUML uses \n). Node ID: <file> with / → _, . → _, stripped of final py extension marker.

Step 2: Enumerate edges

For each file, parse imports via language-specific regex:

• Python: ^(from (?P<module>[\w.]+) import|import (?P<module>[\w.]+)).
• Rust: ^use (?P<module>[\w:]+).
• JS/TS: ^import .* from ["'](?P<module>[^"']+)["'].
• Go: ^\s*"(?P<module>[\w/.]+)" within an import (...) block.

For each imported module, resolve to a file path:

• Try <src_root>/<module_path>.py (replacing . with /).
• Try <src_root>/<module_path>/__init__.py.
• Try other language-appropriate conventions.

If the resolved path is in files, emit an edge <importer_file> → <resolved_file>.

If the resolved path is outside files but inside src_root AND include_external=true, add a ghost node external::<module> and emit the edge.

If the import resolves outside src_root entirely (stdlib, third-party), drop silently.

Step 3: Emit diagram

Resolve renderer per shared doc's resolution order (renderer_override → pharaoh.toml [pharaoh.diagrams].renderer → default mermaid).

Emit the diagram with direction TD (top-down, showing call depth). Caption: <feat_id> — component composition.

For ghost nodes (when include_external=true), group them visually apart where the renderer supports it:

• Mermaid: separate subgraph External block.
• PlantUML: package "external" { ... } block.

Ghost-node styling: dashed outline + muted color (specifics per renderer — consult shared/diagram-tailoring.md for the type_styles lookup).

Step 4: Return

Single RST block. No prose before or after.

Failure modes

• files empty → FAIL.
• Any file in files unreadable → log + skip that file (do not abort unless all files unreadable).
• Cycles in the import graph → emit the diagram anyway (Mermaid/PlantUML handle cycles); log a note.
• Zero edges resolved inside files → emit nodes only, log a note ("no intra-scope edges detected — check files list or use include_external=true").
• include_external=true AND zero in-scope edges AND zero external edges → still emit nodes only, log note.

Non-goals

• No runtime / call-graph inference — that is pharaoh-feat-flow-extract.
• No type hierarchy — that is pharaoh-class-diagram-draft (hand-authored) or a future pharaoh-feat-class-extract.
• No transitive import resolution beyond one hop — depth > 1 explodes scope.
• No dead-code detection — every file in files is a node, whether imported or not.

Last step

After emitting the artefact, invoke pharaoh-diagram-review on it. Pass the emitted artefact (or its need_id) as target. Attach the returned review JSON to the skill's output under the key review. If the review emits any axis with score: 0 or severity: critical, return a non-success status with the review findings verbatim and do NOT finalize the artefact — the caller must regenerate (via pharaoh-diagram-regenerate if available, or by re-invoking this skill with the findings as input).

See shared/self-review-invariant.md for the rationale and enforcement mechanism. Coverage is mechanically enforced by pharaoh-self-review-coverage-check in pharaoh-quality-gate.