Log Evidence Skill

The re-entry point after offline human work. Takes raw conversation notes, observations, or survey results and integrates them into the canvas with proper provenance.

Preflight: Read target canvas file(s) before any Write/Edit

Hard rule. Before issuing Write or Edit against any .claude/canvas/*.yml, use the Read tool on that file in this session. Claude Code's Read-before-Write check requires the Read tool specifically — cat/head/grep via Bash do NOT satisfy it.

Edit vs Write — different cost profiles (verified 2026-05-14):

• Edit (exact-string replacement): Read with limit: 1 satisfies the check at ~50 tokens. State-tracking is per-file, not per-byte — subsequent Edit calls work anywhere in the file. Use this for partial updates against large canvas files (e.g., purpose.yml at 800+ lines).
• Write (full replacement): do a full Read first. Write obliterates the file; you should see what you're about to replace. The limit:1 shortcut is not appropriate here.

ID-bearing entries — scan the ID space before assigning (added 2026-05-15, v0.23.19): When adding a new component, opportunity, solution, or any other ID-bearing entry to a canvas file, run a Bash grep first to confirm the next ID in your prefix sequence is actually free:

grep "^  - id: <prefix>-" .claude/canvas/<file>.yml | sort -u

Replace <prefix> with the canvas's ID prefix (comp for landscape, opp for opportunities, sol for solutions, ht for human-tasks, etc.). Then pick the next free integer. validate_canvas.py has a duplicate-ID check (lines 230-239) that catches the failure on CI, but a duplicate can persist in the working tree for days if CI isn't run between edit and discovery — see roadmap-repo corrections.md 2026-05-15 "Duplicate canvas ID created in landscape.yml" for the worked example.

Original failure mode: anti-pattern #7 instance #5, 2026-05-09 — agent conflated Bash head with the Read tool, lost ~14k tokens to a Write-fail → remedial-full-Read → re-Write loop. The limit:1 discipline (graduated 2026-05-14, v0.23.18) prevents the second-order cost where the agent correctly follows the rule but full-Reads every time. The ID-scan discipline (graduated 2026-05-15, v0.23.19) prevents the related class where the agent reads enough of the file to satisfy the Edit check but not enough to see existing ID assignments — kin to anti-pattern #8 (Stale State Read).

If this skill writes to multiple canvas files, register each one first (limit:1 for Edit-only paths; full Read for Write paths) AND ID-scan any prefix you intend to assign.

See CLAUDE.md Canvas writes — Read before Write for the canonical rule.

When to Use

• After completing a human task from .claude/canvas/human-tasks.yml
• When the user returns from an offline conversation and has findings to record
• When SessionStart reminds about pending human tasks and the user has completed them
• When the user pastes conversation notes or interview summaries

Workflow

1. Check pending tasks:

   • Read .claude/canvas/human-tasks.yml for pending_tasks
   • List them: "You have [N] pending human task(s): [objective summaries]"
   • Ask: "Which task did you complete? Or paste your notes and I'll match them."

2. Guided evidence capture (if user doesn't have a filled template):

   • Who did you talk to? (role and context, not name -- privacy)
   • What did you learn? (open-ended first, let them tell the story)
   • Any direct quotes worth capturing?
   • Anything surprising or contradicting our current assumptions?
   • JTBD signals: functional job, emotional job, social job?
   • Any follow-up conversations needed?

3. Classify the evidence on Gilad's ladder:

   • Single conversation -> anecdotal (0.3)
   • 2 conversations with consistent signals -> anecdotal (0.3), note convergence
   • 3+ triangulated conversations -> data-supported (0.5-0.6)
   • Explain the classification: "One conversation is anecdotal evidence. We'd need 2-3 more to call it data-supported."

4. Update canvas provenance:

   • Identify the relevant canvas file and section (from the task's canvas_refs)
   • Close the learning-target loop (per engine/canvas-guidance.yml#learning_target_coupling): if any answered question carried a [target → <file>#<anchor>] tag, route the captured evidence to that exact entry, then prompt whether the open gap can now move — ON HOLD → OPEN, RE-GATED → met, or a confidence bump. Logging the evidence and retiring the gap are separate steps; the tag makes the second one explicit. If the awaited answer did NOT arrive, say so — the absence is itself a finding (the gap stays open with a note).
   • If the canvas entry has NO provenance object yet (early project), create one:

     provenance:
       evidence_type: anecdotal  # single conversation
       evidence_sources:
         - "interview-YYYY-MM-DD-[role-descriptor]"
       source_classes:
         - external_human
       captured_at: "YYYY-MM-DDTHH:MM:SSZ"
       confidence: 0.3
     

   • If provenance already exists: add to evidence_sources and source_classes arrays
   • Update evidence_type if the new evidence strengthens it
   • Update confidence score with explicit reasoning
   • Update captured_at timestamp

5. Close the source task — coupled to the evidence-write, not a separate afterthought (.claude/canvas/human-tasks.yml):

   Writing evidence and closing the task that produced it are one action, not two. The drift /canvas-health sub-check 8c(b) catches — "evidence exists but the task is still open" — forms precisely when step 4 lands and this step is skipped. Do not report the evidence as logged until this is done.

   • Default (evidence answers the task): move the task from pending_tasks to completed_tasks. Record: completed_at, evidence_logged_to (the canvas file#anchor from step 4), key_findings, source_class: external_human.
   • Partial (some signal, task not fully answered): keep the task in pending_tasks but append to its partial_findings[] (with date + evidence_logged_to) AND state out loud why it stays open and what's still missing — otherwise 8c(b) will flag it next health pass. An un-narrated open task with evidence attached is the drift, not the fix.
   • Registry sync (prevents 8c(c) drift): if this evidence came from a named contributor whose consent or attribution state changed as a result of the conversation (e.g. they granted naming permission), update the canonical attribution registry ($MYCELIUM_ATTRIBUTION_REGISTRY or the private companion repo's .claude/memory/attribution-registry.yml) in the same pass — the registry is canonical (Check 33 reads it). If the registry isn't accessible in this context, say so and leave a note rather than recording consent only in auto-memory (the mismatch 8c(c) exists to catch). Never print a generic_only / project-name carve-out value into output.

Task Cancellation

If the user reports a task couldn't be completed (contact unavailable, timing didn't work, etc.):

1. Ask: "Should we cancel this task or reschedule it?"

2. If cancel: move to completed_tasks with source_class: cancelled and a note explaining why

3. If reschedule: update the task's objective or target_persona if needed, keep in pending_tasks

4. Either way: "The evidence gap still exists. Consider /mycelium:handoff to plan an alternative approach."

5. Check for contradictions:

   • Compare findings against existing canvas data
   • If findings contradict assumptions: flag clearly
     • "This contradicts [canvas section / assumption]. The user said [X] but we assumed [Y]."
     • Suggest: "Consider running /mycelium:devils-advocate to stress-test this assumption, or update the canvas with /mycelium:canvas-update."
   • If findings support assumptions: note the confirmation
     • "This supports [ca