ad-ground

name	ad-ground
description	Four-source pre-implementation research — official docs, validated implementation references (open-source repos, Stack Overflow / forum answers, blog posts, gists), in-repo patterns, and git history — then synthesize a happy path, persist its claim-to-source evidence as an auditable project record, and gate any deviation before code is written. Grades evidence and confidence per WORKFLOW §17; routes insufficient evidence to ad-spike. Auto-invokes on non-trivial work, refactors, library or pattern selection, "research before coding", "before implementing", "which library", "which pattern", "how to approach", "ground before coding". Workflow-operational counterpart to WORKFLOW.md §4 + §5.
summary	Four-source pre-implementation research + versioned claim-to-source evidence record, happy-path synthesis, deviation gate, and proportional evidence grading. WORKFLOW §4 + §5 + §17.

<background_information> Implements WORKFLOW §4 + §5 end-to-end as one research pass. The four sources are joined by AND, not OR — every non-trivial change runs the full research pass, then synthesizes a happy path, persists the evidence trail, then justifies any deviation. This skill writes a ground record, never production code.

Codex auto-trigger on description keywords is less mature than Claude Code's. If auto-invocation does not fire on a non-trivial change, invoke this skill manually before implementing. </background_information>

Step 0 — scope the research scope. Confirm what is being researched in one sentence. The research scope is the smallest verifiable surface that captures the change: a function to add, a library to pick, a pattern to apply. If broader than one sentence, ask the user to narrow. Skip the skill on genuinely trivial diffs (rename, typo, one-line refactor on a tested path).

Step 1 — four-source research pass, all four required:

Source A — official documentation. For each language and library in scope, cite the canonical doc URL and version. Read the relevant section. Ask the user for a known-good link rather than fabricating one. Output: bulleted citations, one per language/library, each with URL plus a one-line summary.

Source B — validated implementation references. ≥1 (prefer 2–3) public reference (open-source repo, Stack Overflow / forum answer, blog post, gist) solving the same technical research scope with similar techniques. Match is technical, not domain. Cite <source>:<locator> — <repo>:<path>:<line-range> for repos, <URL> for Stack Overflow / forum / blog / gist — and quote the relevant block. Never paraphrase from training memory. If search is inconclusive, ask the user for a known reference.

Source C — in-repo examples. Grep / glob for analogous patterns. Cite <file>:<line> plus a one-line description of how the existing example handles the same shape. If the codebase has no analog, state that explicitly.

Source D — git history. Run git log --all --oneline -- <relevant-paths>, git log --all --grep=<keyword>, sweep sibling active branches. Cite <commit-sha> plus touching file path and a one-line description. If empty, state "no prior attempt found." Narrow with --grep or -S on multi-thousand-commit repos.

Step 2 — happy path synthesis. In one paragraph, name the most-grounded approach for the research scope and cite at least one source per Source A / B / C. Source D included when it produced a hit; otherwise mark "no prior attempt found." The paragraph is the canonical answer to "what is the canonical, idiomatic way to solve this here?"

Step 3 — deviation gate. If the implementation about to be written deviates from the happy path, write the justification first. Must name the specific constraint, evidence, or trade-off forcing the deviation — generic "we want it differently" is insufficient. If the justification cannot be written confidently, loop back to Step 1 and look harder; do not deviate without it. Prescriptive gate, not descriptive — write the answer down.

Step 4 — confidence checkpoint. Soft verdict, in two modes chosen by stakes times irreversibility.

Quick mode (the default for small, reversible scopes) — the coverage checklist:

• A consulted (≥1 official-doc citation per language/library)
• B consulted (≥1 implementation-reference citation, with cite-and-fetched code)
• C consulted (in-repo analog cited or "no analog found" stated)
• D checked (commits / branches surveyed; hit cited or "no prior attempt found")
• Happy path declared (Step 2)
• Deviation, if any, justified (Step 3)

Full mode (when stakes times irreversibility justify it) — grade the evidence per WORKFLOW §17, on top of the coverage checks:

• Seal each load-bearing claim in the happy path High / Medium / Low / Very-low (Axis 1), each with its provenance — citation, date, access method. A claim you cannot source cannot be sealed High. Where sources genuinely disagree, record the positions side by side rather than forcing a consensus.
• Report one Axis-2 verdict for the decision: Strong (proceed), Conditional (proceed with a named mitigation), or Insufficient / spike-first (do not proceed; the gap is retirable by experiment). The bar for Strong scales with stakes times irreversibility.
• An Insufficient / spike-first verdict is the handoff to ad-spike (WORKFLOW §14): the technique is not yet grounded enough to build on, and a staged spike is how it gets retired.

If any coverage check fails, or the full-mode Axis-2 verdict is not Strong, surface the gap to the user and ask before proceeding. Do not block. The user retains authority to skip; the discipline is in surfacing.

Step 5 — persist the evidence receipt. Chat citations are not an audit trail. Before the decision directs a non-trivial repository change, write a versioned ground record under doc/research/. It is a receipt for an already-defined implementation path, not an ad-research study answering an open question; both share the directory and monotonic number ledger.

When this pass is the Acquire phase of ad-research, the study is already the durable evidence artifact: put the same claim-to-source map in that study and do not create a duplicate ground receipt.

From the consumer root run node .agents/skills/ad-adr/scripts/next-number.mjs doc/research. Use JSON next. Stop until access is resolved if unreadable is non-empty, or for a numbering decision if exhausted is true. Write doc/research/<NNNN>-ground-<slug>.md from references/record-template.md. Every load-bearing claim gets an E<N> section with a §17 strength and one or more source IDs; the source register carries at least one A, B, C, and D source, each with citation, access date, and access method. Record an empty git-history search as D1, including the command and its no prior attempt found result — absence is evidence only when the search is reproducible.

Set Decision ref to the task, spec, ADR, or other durable project artifact the record supports. Add the ground record's repository-relative path to that artifact's Evidence ref field; when a task tracks the work, update that field or append the path to its dated Notes entry. Do not create a new planning artifact solely to hold a trivial decision.

Validate the completed receipt before implementation: node .agents/skills/ad-ground/scripts/validate-record.mjs doc/research/<NNNN>-ground-<slug>.md. Proceed only when valid is true and unreadable is empty. The offline checker proves the claim-to-source map is structurally complete; it does not prove an external source's content. Reopen every cited source during review or audit. A receipt without that re-check is a trace, not proof.

<output_contract> The output-format skeleton lives in references/output-format.md — a single structured message that reports the record path, validation result, decision, and confidence in that order.

No production code is written by this skill. The durable ground record feeds the next turn or another skill. </output_contract>

Next

• Implement per the synthesized happy path and link the validated ground record from the governing task, spec, or ADR.
• /ad-task if the work needs explicit decomposition into checkbox-toggle work units.
• /ad-review main..HEAD (or current scope) before merge — WORKFLOW §10.
• /ad-adr if the deviation gate surfaced a binding architectural decision.