challenge-gen

name	challenge-gen
description	Use after /diagnose-agent when you have a struggle profile and need training challenges. Generates edge-case and commit-replay challenges calibrated to weak areas. Keywords: challenge, training, improvement, active-learning, edge-case, replay, agent, weakness.
argument-hint	<agent-name>
disable-model-invocation	false
user-invocable	true
allowed-tools	["Read","Grep","Glob","Write","WebSearch","WebFetch","Task","Bash(git:*)","Bash(wc:*)","Bash(mkdir:*)"]
context	inline

Challenge Gen: Targeted Agent Training Challenges

You are running challenge-gen — generating targeted challenges to exercise an agent's weak areas. Target agent: $ARGUMENTS

When to Use

• After /diagnose-agent produces a struggle profile — generate challenges that target identified weaknesses
• When an agent repeatedly struggles with specific task types and needs deliberate practice
• Before /active-learn to create a curated challenge set for a training cycle
• When onboarding an agent to a new domain and want calibrated difficulty ramps

Don't Use When

• No /diagnose-agent profile exists for the target agent — challenges generated without a struggle profile are poorly calibrated (run /diagnose-agent first)
• Agent has no learnings history and no owned files with git activity — both strategies need a signal source; a brand-new agent has none
• You want to run challenges rather than generate them — use /challenge-run to execute an existing challenge set

Prerequisites

This skill requires the following infrastructure:

• team.yaml — Agent must be listed in .claude/team.yaml with ownership patterns defining their domain (how to create)
• diagnose-agent profile — A /diagnose-agent struggle profile for the target agent should exist in the current session context; without it the skill falls back to basic profiling from learnings alone, producing less calibrated challenges (how to generate)
• learnings file — .claude/tackline/memory/agents/<agent>/learnings.md should exist with accumulated history; used to extract Gotchas and known weaknesses when no upstream profile is available (populated by /retro and /active-learn)

If the diagnose-agent profile is missing, the skill warns and continues with basic profiling — challenges will be generated but may not be well-targeted to the agent's actual weaknesses. If team.yaml is missing or the agent is not listed, the skill stops and asks the user to select an agent from the available list.

How It Works

Serial (default):

Detect upstream /diagnose-agent output (or accept $ARGUMENTS)
  -> Validate agent exists, extract ownership areas
    -> Strategy A: Research domain edge cases (WebSearch + codebase)
      -> Strategy B: Find commit-replay candidates (raw git)
        -> Assemble 3-5 challenges with quality gate
          -> Write challenges to .claude/tackline/memory/agents/<name>/challenges/
            -> Emit pipe format output

Parallel mode (pass parallel in $ARGUMENTS):

Detect upstream /diagnose-agent output (or accept $ARGUMENTS)
  -> Validate agent exists, extract ownership areas
    -> [concurrently]
         Agent A: Research domain edge cases (WebSearch + codebase)
         Agent B: Find commit-replay candidates (raw git)
    -> Collect results from both agents
      -> Assemble 3-5 challenges with quality gate
        -> Write challenges to .claude/tackline/memory/agents/<name>/challenges/
          -> Emit pipe format output

---

Phase 0: Detect Input and Validate

0a. Check for Upstream /diagnose-agent Output

Search conversation context for the pipe-format pattern:

## Struggle Profile: <agent-name>

**Source**: /diagnose-agent

If found:

1. Read the upstream output. State: "Reading N items from /diagnose-agent output above."
2. Extract: agent name, WEAKNESS items, GAP items, STRENGTH items, difficulty calibration
3. Record the upstream **Pipeline** field for provenance

If not found:

1. If $ARGUMENTS provides an agent name, proceed with basic profiling (Phase 0b)
2. If $ARGUMENTS is empty, list available agents from .claude/team.yaml and ask the user which to target. Stop and wait.
3. Warn: "No /diagnose-agent output detected. Running with basic profiling — for richer challenges, run /diagnose-agent <name> first."

0b. Validate Agent and Extract Ownership

1. Read .claude/team.yaml and confirm the agent name exists in the members list
2. Extract the agent's owns patterns (file globs defining ownership areas)
3. Read .claude/tackline/memory/agents/<name>/learnings.md if it exists — scan for Gotchas and known weaknesses
4. If no upstream struggle profile exists, construct a minimal one from learnings Gotchas + sparse categories

---

Parallel Dispatch Mode

In parallel mode ($ARGUMENTS contains parallel), run Phase 1 and Phase 2 as concurrent background Task agents after Phase 0 completes. This roughly halves wall-clock time because Strategy A (WebSearch + codebase) and Strategy B (git history) are fully independent.

When to use parallel mode: When the agent's owned area is broad (many files, many weaknesses) and both strategies are expected to yield candidates. For narrow profiles or small codebases, serial mode is cheaper and produces equivalent results.

Assessment before dispatch: After Phase 0 validates the agent and extracts ownership, confirm that both strategies have meaningful scope before launching both agents:

• Strategy A has scope if: ≥1 WEAKNESS or GAP item exists and the owned file globs match files in the repo
• Strategy B has scope if: the agent has owned files with recent commits (git log --oneline --since="60 days ago" -- <owns-patterns> returns ≥1 result)

If only one strategy has scope, fall back to serial for the active strategy only.

Dispatch (parallel mode)

After Phase 0 completes, launch both agents concurrently:

Strategy A agent:

Task({
  subagent_type: "general-purpose",
  run_in_background: true,
  prompt: "<Strategy A agent prompt — see template below>"
})

Strategy B agent:

Task({
  subagent_type: "general-purpose",
  run_in_background: true,
  prompt: "<Strategy B agent prompt — see template below>"
})

Collect results from both agents before proceeding to Phase 3.

Agent Prompt Templates

Strategy A: Domain Edge Cases Agent Prompt

You are running Strategy A of challenge-gen for agent: <agent-name>.

## Context

Agent owns: <owns-patterns>
Struggle profile source: <upstream source or "basic profiling">

Weaknesses to target:
<list each WEAKNESS item from struggle profile>

Gaps to target:
<list each GAP item from struggle profile>

Difficulty calibration: <novice | intermediate | expert | adversarial>

## Your Task

Research domain edge cases for the weaknesses and gaps listed above. You are Strategy A — do NOT use git history (that is Strategy B's job). Use WebSearch and codebase reading only.

### Step 1: Codebase Edge Cases

Search the agent's owned files for error-prone patterns:

- Files with high cyclomatic complexity (many conditionals, nested logic)
- Error handling paths that are rarely exercised
- Configuration edge cases (empty inputs, boundary values, unusual combinations)
- Cross-cutting concerns the agent's learnings don't mention

Use Grep and Glob to find files matching these patterns: <owns-patterns>

### Step 2: External Edge Cases

Use WebSearch to find real-world edge cases related to each weakness:
- Search for CVEs, security advisories, or known bugs in the technology stack
- Search Stack Overflow for highly-voted edge case questions in the domain
- Search GitHub issues for "unexpected behavior" or "edge case" in related projects
- Search for framework-specific gotchas the agent may not have encountered

For each external finding, verify it applies to the codebase by checking:
- Is the relevant technology/library actually used? (check package files, imports)
- Is the vulnerable pattern present in owned files?
- Has it already been addressed? (check git history for related fixes)

### Step 3: Select Best Edge Cases

From all candidates, select 2-3 that:
- Target a specific WEAKNESS or GAP from the profile above
- Have clear acceptance criteria (the "right answer" is verifiable)
- Contain a non-obvious trap (something that makes the naive solution wrong)
- Are grounded in real scenarios (not hypothetical)

## Output Format

Report your findings as a structured list. For each candidate:

**Edge Case <N>:** <title>
- targeted_weakness: <WEAKNESS or GAP name from profile>
- scenario: <what the agent is asked to do>
- trap: <the non-obvious thing that makes the naive solution wrong>
- acceptance_criteria: <how to evaluate pass/fail>
- grounding: <URL, file path, or CVE that makes this real>

If no candidates meet the quality bar, state: "No qualifying edge cases found — Strategy A produced 0 candidates."

Strategy B: Commit-Replay Agent Prompt

You are running Strategy B of challenge-gen for agent: <agent-name>.

## Context

Agent owns: <owns-patterns>
Struggle profile source: <upstream source or "basic profiling">

Weaknesses to target:
<list each WEAKNESS item from struggle profile>

Gaps to target:
<list each GAP item from struggle profile>

Difficulty calibration: <novice | intermediate | expert | adversarial>

## Your Task

Find commit-replay challenge candidates in the agent's ownership area. You are Strategy B — use git history only. Do NOT use WebSearch (that is Strategy A's job).

### Step 1: Find Candidate Commits

Run these git commands against the owned file patterns:

```bash
# Recent fix commits in owned files
git log --oneline --since="60 days ago" -- <owns-patterns> | head -30

# Find fix: commits that follow feat: commits on same files
git log --format="%H %s" --since="60 days ago" -- <owns-patterns>

Scan for fix: commits. For each, check if a feat: commit on the same files preceded it within 7 days.

Prioritize:

• fix_after_feat commits (the fix is the challenge — can the agent get it right the first time?)
• Commits touching frequently-changed files (areas where correctness is repeatedly hard)
• Commits with detailed messages (better context for the challenge prompt)

Step 2: Extract Challenge Material

For each candidate commit:

git show --format="%B" --no-patch <commit-hash>   # commit message -> challenge prompt
git show --format="" <commit-hash>                  # diff -> ground truth
git show <commit-hash>^:<file-path>                 # file before commit -> starting point
git rev-parse <commit-hash>^                        # parent hash -> base_commit

Record the parent hash as base_commit — the state before the fix. This is what /challenge-run uses for worktree isolation.

Step 3: Select Best Replay Candidates

From all candidates, select 1-2 that:

• Target a specific WEAKNESS or GAP from the profile above
• Have a self-contained diff (not sprawling across 10+ files)
• Have enough context in the commit message to understand intent
• The "before" state is a plausible starting point (not mid-refactor)

Output Format

Report your findings as a structured list. For each candidate:

Commit Replay :

• targeted_weakness: <WEAKNESS or GAP name from profile>
• base_commit:
• commit_hash:
• scenario: <commit message or paraphrase — what the agent is asked to do>
• trap:
• acceptance_criteria: <how to evaluate — match the actual diff>
• files_changed:

If no candidates meet the quality bar, state: "No qualifying commit-replay candidates found — Strategy B produced 0 candidates."

---

## Phase 1: Research Domain Edge Cases — Strategy A (default)

For each WEAKNESS and GAP item from the struggle profile, research real-world edge cases in that domain.

### 1a. Codebase Edge Cases

Search the agent's owned files for patterns that are commonly error-prone:

```bash
# Find complex or unusual patterns in owned files
git log --oneline --all --since="60 days ago" -- <owns-patterns>

Look for:

• Files with high cyclomatic complexity (many conditionals, nested logic)
• Error handling paths that are rarely exercised
• Configuration edge cases (empty inputs, boundary values, unusual combinations)
• Cross-cutting concerns the agent's learnings don't mention

1b. External Edge Cases

Use WebSearch to find real-world edge cases related to each weakness:

• Search for CVEs, security advisories, or known bugs in the technology stack
• Search Stack Overflow for highly-voted edge case questions in the domain
• Search GitHub issues for "unexpected behavior" or "edge case" in related projects
• Search for framework-specific gotchas the agent may not have encountered

For each external finding, verify it applies to the codebase by checking:

• Is the relevant technology/library actually used? (check package files, imports)
• Is the vulnerable pattern present in owned files?
• Has it already been addressed? (check git history for related fixes)

1c. Select Best Edge Cases

From all candidates, select 2-3 that:

• Target a specific WEAKNESS or GAP from the struggle profile
• Have clear acceptance criteria (the "right answer" is verifiable)
• Contain a non-obvious trap (something that makes the naive solution wrong)
• Are grounded in real scenarios (not hypothetical)

---

Phase 2: Find Commit-Replay Candidates — Strategy B (default)

Identify real commits in the agent's ownership area that can be turned into replay challenges.

2a. Find Candidate Commits

# Recent fix commits in owned files
git log --oneline --since="60 days ago" -- <owns-patterns> | head -30

# Find fix: commits that follow feat: commits on same files
git log --format="%H %s" --since="60 days ago" -- <owns-patterns>

Scan for fix: commits. For each, check if a feat: commit on the same files preceded it within 7 days.

Prioritize:

• fix_after_feat commits (the fix is the challenge — can the agent get it right the first time?)
• Commits touching frequently-changed files (areas where correctness is repeatedly hard)
• Commits with detailed messages (better context for the challenge prompt)

Filter results to files matching the agent's owns patterns.

2b. Extract Challenge Material

For each candidate commit:

# Get the commit message (this becomes the challenge prompt)
git show --format="%B" --no-patch <commit-hash>

# Get the diff (this is the ground truth, hidden from the agent)
git show --format="" <commit-hash>

# Get the file state BEFORE the commit (this is the starting point)
git show <commit-hash>^:<file-path>

# Get the parent commit hash (this is the base_commit for worktree isolation)
git rev-parse <commit-hash>^

Record the parent hash as the base_commit — the state of the repo before the fix was applied. This is the commit that /challenge-run will use to create a worktree at the pre-fix state.

2c. Select Best Replay Candidates

From all candidates, select 1-2 that:

• Target a specific WEAKNESS or GAP from the struggle profile
• Have a self-contained diff (not sprawling across 10+ files)
• Have enough context in the commit message to understand intent
• The "before" state is a plausible starting point (not mid-refactor)

---

Phase 3: Assemble Challenges

Combine edge-case and commit-replay candidates into a final set of 3-5 challenges.

In parallel mode, wait for both background agents to complete, then collect their structured output before proceeding. Treat agent output sections ("Edge Case N:" and "Commit Replay N:") as the candidate pool that feeds Phase 3a and 3b below.

3a. Balance and Calibrate

• Mix strategies: at least 1 edge-case and 1 commit-replay (if candidates exist for both)
• Calibrate difficulty using the upstream Difficulty Calibration level:
  • novice: challenges should have clear signals and a single trap
  • intermediate: challenges should require connecting 2-3 concepts
  • expert: challenges should involve cross-cutting concerns or subtle interactions
  • adversarial: challenges should have multiple valid-looking approaches where only one is correct
• Each challenge must target a different WEAKNESS or GAP (no doubling up)

3b. Quality Gate

Every challenge MUST pass these checks before inclusion:

1. Targets a specific weakness — maps to a named WEAKNESS or GAP from the struggle profile
2. Has clear acceptance criteria — can evaluate agent output as pass/fail
3. Has a hidden trap — something non-obvious that the naive approach gets wrong
4. Is grounded — based on real code, real CVEs, real commits, or real Stack Overflow patterns (not hypothetical)
5. Is self-contained — the agent can attempt it without needing the full project context

Drop any challenge that fails a check. If fewer than 3 survive, return to Phase 1 or 2 for more candidates.

---

Phase 4: Write and Emit

4a. Write Challenge File

mkdir -p .claude/tackline/memory/agents/<name>/challenges

Write challenges to .claude/tackline/memory/agents/<name>/challenges/<timestamp>-challenges.md using this structure:

# Challenges for <agent-name>

Generated: <date>
Source profile: /diagnose-agent (or "basic profiling")
Difficulty level: <novice | intermediate | expert | adversarial>

## Challenge 1: <title>

**Strategy**: edge-case | commit-replay
**Base commit**: <parent-hash> *(commit-replay only)*
**Targeted weakness**: <WEAKNESS or GAP name from profile>
**Difficulty**: <level>

### Scenario

<What the agent is asked to do — this is what the agent sees>

### Acceptance Criteria

<How to evaluate the agent's output — pass/fail conditions>

### Hidden Trap

<The specific thing that makes this hard — NOT shown to the agent>

### Ground Truth

<The correct approach or actual diff — for evaluation only>

---

## Challenge 2: ...

4b. Emit Pipe Format Output

Output the challenge set in pipe format for downstream consumption:

## Challenge Set: <agent-name>

**Source**: /challenge-gen
**Input**: <agent-name>
**Pipeline**: <upstream pipeline> -> /challenge-gen (N challenges)

### Items (N)

1. **<challenge-title>** — <one-line description>
   - scenario: <brief scenario summary>
   - targeted_weakness: <WEAKNESS or GAP name>
   - difficulty: novice | intermediate | expert | adversarial
   - acceptance_criteria: <how to evaluate>
   - hidden_trap: <what makes it hard>
   - strategy: edge-case | commit-replay
   - base_commit: <hash> *(commit-replay only)*

2. ...

### Difficulty Calibration

Agent coverage: <percentage from upstream or estimated>
Challenge level: <novice | intermediate | expert | adversarial>
Strategy mix: <N edge-case, M commit-replay>

### Summary

<One paragraph synthesizing the challenge set: what weaknesses are targeted, what strategies were used, what difficulty level, and what growth the challenges are designed to produce.>

---

Guidelines

1. Challenges, not tests. Challenges are designed to produce growth through deliberate practice, not to measure current ability. Err toward slightly above the agent's level — struggle is the point.
2. Real over hypothetical. Every challenge must be grounded in real code, real CVEs, real commits, or real community knowledge. Hypothetical scenarios do not transfer to real work.
3. One weakness per challenge. Each challenge targets exactly one WEAKNESS or GAP. Compound challenges dilute the training signal.
4. Hidden traps are essential. A challenge without a non-obvious trap is just a task. The trap is what forces the agent to develop new patterns rather than applying existing ones.
5. Graceful degradation. No upstream profile? Do basic profiling. No web search results? Use codebase-only edge cases. Always produce something useful.
6. Commit-replay integrity. When extracting commit material, never modify the ground truth diff. The whole point is that the actual change is the answer. The base_commit must be a real commit hash from git history (output of git rev-parse <commit>^), never fabricated or modified — /challenge-run depends on it for worktree isolation.
7. Do not show hidden traps to the agent. The challenge file separates what the agent sees (scenario + acceptance criteria) from what the evaluator knows (hidden trap + ground truth). This separation is critical.
8. Cap at 5 challenges. More than 5 creates evaluation overhead without proportional learning benefit. If many weaknesses exist, prioritize by severity.
9. Write provenance. Record which profile items each challenge targets so /active-learn can track which weaknesses have been exercised and which remain untouched.

See also: /challenge-run (execute the challenges produced here against the agent — uses base_commit for worktree isolation in commit-replay challenges); /diagnose-agent (generate the struggle profile that feeds this skill); /active-learn (run a full training cycle using challenge sets).