discovery

name

discovery

description

Ground a task in the existing codebase before specification — grep for prior art, read similar features, surface inherited gotchas, write discovery.md. Load this skill whenever you're running scout during /define or /orchestrate, whenever a task touches an area of the codebase you have not read in this session, whenever the task mentions a feature name that might already exist, or whenever recent_learnings flags a gotcha or pattern near the task. Prevents specs built on phantom assumptions.

Discovery

The spec is only as good as its contact with reality. Discovery is the contact — the codebase scan that happens before the spec is drafted, so assumptions are validated instead of invented.

When to Use

• At the start of /define or /orchestrate, in parallel with critic
• When a task touches code that already exists (even if the user framed it as "new")
• When learnings from prior sessions suggest prior art or inherited gotchas
• When the task involves an area of the codebase you have not read in this session

When NOT to Use

• Single-line fixes where the file is already named in the request
• Greenfield projects with no existing code to scan
• Typo corrections or documentation-only changes
• Follow-ups to a recently completed task where the spec just ran

Core Process

1. Scope the search

Identify the keywords, package names, and feature words from the task. Build a short list — five to ten terms — that will feed into grep.

Do not try to read the whole codebase. The goal is to check whether the task overlaps with existing code, not to produce a map of everything.

2. Grep for prior art

Run grep for each keyword across the repository. Skim the hits for:

• Functions or types that already implement what the task asks for
• Files named after the feature (rate_limiter.go, auth_middleware.py)
• Tests that cover similar behavior

Cite every hit with a file path and line number. If you cannot cite a path, you cannot claim the hit.

3. Read similar features

For the closest two or three prior-art matches, read the file. Note:

• The conventions used (naming, structure, error handling)
• The dependencies imported
• The tests colocated with the feature
• Any TODO, FIXME, or HACK comments that hint at known gotchas

4. Check learnings

Read recent_learnings from session-start context. Learnings flagged gotcha or pattern that relate to the task's area become Inherited Gotchas in the discovery artifact.

5. Write discovery.md

Populate the four sections of docs/specs/<slug>/discovery.md:

• Existing Surface — every file/function cited, with a one-line relevance note
• Patterns to Follow — each pattern with an example path
• Inherited Gotchas — each gotcha with evidence
• Handoff to main Claude — what should fold into Assumptions and Technical Approach

Stay terse. Headline findings only. Detailed forensic notes do not belong here.

Common Rationalizations

Shortcut	Reality
"It's a new feature, nothing exists yet."	You have not grepped. The codebase has surprised you before. Grep first, then claim.
"I already read this codebase last week."	Memory fades. Files change. A five-minute grep catches what memory misses.
"The task description is clear — no discovery needed."	Clear tasks still touch existing code. Clear does not mean isolated.
"I'll just list the file paths I think are relevant."	Without citations, your list is speculation. Every entry needs a path you actually opened.
"Critic already checks for existing code."	Critic's role was narrowed. Discovery is your job now. Do it.

Red Flags

• A finding asserted without a file path
• "Existing Surface" section left empty on a non-greenfield task
• Patterns claimed without an example path
• No mention of learnings despite recent_learnings being populated
• Handoff section rewriting the task — you are not here to redesign, only to surface
• Discovery artifact longer than the spec it precedes

Verification

• Every claim in discovery.md cites a file path
• At least one grep was run for each keyword extracted from the task
• Similar-feature files were read, not just skimmed for names
• recent_learnings were checked for gotchas in the task's area
• Handoff section names specific items to fold into the spec, not general advice
• Discovery artifact is shorter than the spec template — not a second spec

Pair With

• core/spec-generation — discovery.md is one of the four required artifacts in the spec directory; this skill owns its shape.
• core/skill-discovery — routes "grounding a task in existing code" to this skill.
• core/orchestration — main Claude spawns scout (which loads this skill) during Phase 1 in parallel with critic.