Delegate Repo Analysis

delegate-repo-analysis

Parent-orchestrator pattern for codebase workflows: reverse, refactor, build, and any "look at this repo and produce structured output" task. The parent reads ONLY subagent reports and final artifacts. All worktree reads go to leaf subagents.

When to Use

• An active skill (regent-reverse, regent-refactor, regent-build, or similar) targets a worktree (clone, spec dir, refactor output, vendor source).
• The work involves >2 files of source reading, per-file deep analysis, or multi-file mutation.
• The user said any of: "派子agent去测试", "let the subagent do it", "用 subagent-driven-development", or similar delegation cues.

Don't use for:

• Tasks that don't touch a worktree (pure Q&A, planning, single-file edits).
• Tasks where the parent IS the implementer (one-shot scripts, small fixes).

The boundary

┌─────────────────────────────────────────────────────────────┐
│  Parent (you)                                               │
│  - Acquire worktree (clone, mkdir, ls)         — OK direct  │
│  - Dispatch leaf subagents per step            — ALWAYS     │
│  - Read subagent summaries, spec output, diff  — OK direct  │
│  - Run pytest / go test / make / final smoke   — OK direct  │
│                                                             │
│  Leaf subagent (delegated)                                  │
│  - read_file / search_files on source files    — NEVER      │
│    done by parent                                           │
│  - Per-file deep read                         — ALWAYS     │
│  - Per-file write (spec sections, code edits) — ALWAYS     │
└─────────────────────────────────────────────────────────────┘

If the parent runs read_file on more than two source files in the worktree, the boundary has been crossed. User has explicitly corrected this pattern:

"你怎么自己开始干了, 不是应该先把他的仓库clone下来, 然后你派子agent去测试吗"

The three non-negotiable subagent prompt elements

Every leaf subagent prompt MUST include:

1. Exact file/path list. "Read /tmp/foo/X, /tmp/foo/Y. NOT others." Subagents without a path list drift into the whole repo.
2. HARD BUDGET in lines or files. "Total reads < 800 lines." Without a budget, "read every test file" prompts time out at 600s on real repos (17 test files × 500 LOC = 9.8K lines is a known timeout case).
3. Concrete deliverable path. "Write /path/to/output.md. Format follows SKILL.md §X. Cite file:line for every rule." Subagents without a deliverable path drift into exploration and never converge.

Pattern: split a large task

When the cumulative source surface of a task exceeds ~5000 lines:

1. List stage — ls *_test.go, get counts. Pick the 3-5 files that cover the public API the spec cares about.
2. Search stage — for each candidate fixture in the spec, search the picked files for the discriminative test (pattern: function name
   • invocation). Read 30-line windows.
3. Cite stage — every oracle entry pins test_file:start-end.

Dispatch 2-3 parallel subagents, each with its own budget. See references/reverse-and-refactor-delegation.md §2 for a worked example (cobra reverse, three parallel subagents, each ≤800/200/400 lines).

The clarification-only refactor pattern

For regent-refactor with strategy: side-by-side, when the spec edit is a pure clarification (no inputs/outputs/error-paths change), the correct rewriter output is zero source diff.

diff -r --brief <source_dir> <out_dir>  # ignore .git, .venv, __pycache__

If every tracked file is identical AND all three grading keys (pytest + functional-checklist + test-oracle) are green, the refactor PASSED. State this explicitly in the report:

Clarification-only refactor: zero source changes, spec edit is documented intent only.

Don't treat zero-diff as "rewriter failed to act" — verify first.

Spec-debt watch list

Common conflation when writing inventory/functional-checklist.md:

• Library fallback vs CLI fallback. Library functions fall back; CLIs reject unknown --<flag> values via argparse choices=. Pin library behaviour in test-oracle.md, CLI behaviour in functional-checklist.md. Putting library fallback into the CLI checklist produces a failing entry that has to be walked back.

• Self-test vs contract. if __name__ == "__main__" blocks, Rust #[cfg(test)] mod tests, Go func TestXxx(*testing.T) are NOT contract — they are test scaffolding. The real func main() of a binary IS contract. Don't conflate.

• Deprecation markers as signal. FIXME Gt is unused by cobra... marks back-compat helpers. The spec should record them as "kept for back-compat, planned for v2 removal" — not as live API.

Pitfalls

1. Parent reads >2 source files directly — cross the boundary, the user will correct it. Dispatch instead.
2. Unbounded read in subagent prompt — "read every test file" with no budget causes 600s timeout. Always pin a HARD BUDGET.
3. No deliverable path in subagent prompt — subagent explores forever, never writes. Always pin a concrete output file path.
4. Treating zero-diff as failure — for clarification-only refactors, zero source diff is the correct outcome. Verify by diffing the two trees, not by counting edits.
5. Conflating library and CLI behaviour in checklists — produces false failures. Library behaviour goes in oracle, CLI behaviour in checklist.

One-shot recipe

# 1. Acquire the worktree (parent does this directly, one command).
git clone --depth 1 https://github.com/<owner>/<repo>.git /tmp/<repo>

# 2. Dispatch 2-3 parallel subagents for the heavy lifting.
# Each prompt MUST include: file list, HARD BUDGET, deliverable path.
delegate_task(goal="...", context="Read these files: A, B, C.
HARD BUDGET: <800 lines total. Write output to /path/to/X.md.")

# 3. Accept subagent reports, dispatch the next phase (often a build
# agent that consumes the spec to blind-rebuild the project).

# 4. Run final verification on the rebuild output (parent does this):
go test ./...
diff -r --brief <source> <rebuild>