Drift Prevention

Long sessions accumulate context that gradually diverges from the source of truth. This skill defines a re-anchoring protocol that rebuilds ground truth from artifacts rather than trusting session memory.

The Problem

After 30+ minutes of implementation, agents commonly:

• Forget specific acceptance criteria while chasing implementation details
• Lose track of which criteria are met vs outstanding
• Drift from the spec when encountering unexpected complexity
• Accumulate stale assumptions from earlier in the session that no longer hold

This is a direct consequence of treating agents as logic engines with perfect memory rather than orchestrators with finite attention. The anchoring protocol below rebuilds ground truth from source artifacts, not session memory. Source: Pierce Lamb Deep Trilogy — "treat Claude as an orchestrator with finite attention, not a logic engine."

Pre-Step: Gather Issue Context Bundle

Before executing this skill, gather the issue context bundle (see issue-lifecycle/references/issue-context-bundle.md). Include comment context in drift checks — comments may contain decisions that change scope, human overrides that alter acceptance criteria, or dispatch results that affect what remains to be done.

Anchoring Protocol

Before every task (or when triggered), re-read these four sources in order:

1. Active Spec

Read the PR/FAQ or spec document linked in the issue's linear frontmatter field:

• Frontmatter -- exec mode, status, research readiness
• Acceptance criteria -- The complete checklist. Mark each as addressed/not-addressed.
• Open questions -- Any unresolved questions that might affect implementation

2. Git State

Check the current implementation state:

• git diff --stat since last commit
• Uncommitted changes and their alignment with acceptance criteria
• Current branch and its relationship to the target branch
• Any stashed changes that might be relevant

3. Issue State

Read the current issue from the project tracker:

• Status -- Should be In Progress if work is active
• Labels -- exec:* mode, spec:* lifecycle stage, any blockers
• Assignment -- Confirm the agent is the assignee
• Comments -- Recent updates, human feedback, or scope changes

4. Review Comments

Check for unresolved feedback:

• Adversarial review findings (from /ccc:review output)
• PR review threads with unresolved comments
• Carry-forward items from previous implementation rounds

When to Anchor

Trigger	Action
Session exceeds 30 minutes	Auto-suggest anchoring
Context compaction occurs	Mandatory anchor before continuing
Switching between tasks	Anchor to the new task's spec
After debugging a tangent	Anchor to verify you're back on track
Before claiming "done"	Final anchor to verify all criteria met
Manual trigger (/ccc:anchor)	Full protocol execution

Anchor Output Format

After re-reading all sources, produce a concise alignment summary:

## Anchor Check — [Issue ID]

**Spec:** [spec title] | **Mode:** [exec mode] | **Status:** [spec status]

### Acceptance Criteria
- [x] Criterion 1 — implemented in [file:line]
- [ ] Criterion 2 — not yet started
- [~] Criterion 3 — partially implemented, [what remains]

### Drift Detected
- [Any misalignment between implementation and spec]
- [Any scope creep beyond acceptance criteria]

### Open Items
- [Unresolved review comments]
- [Open questions from spec]

### Next Action
- [The single most important next step]

Automatic vs Manual

• Automatic: The skill activates as a background check when session length or context usage crosses thresholds. It surfaces a warning if drift is detected.
• Manual: /ccc:anchor runs the full protocol and produces the alignment summary output.

Integration with Other Skills

• execution-modes: Anchor protocol adapts to the current exec:* mode. In exec:tdd, it also checks test state. In exec:checkpoint, it verifies gate status.
• context-management: When context exceeds 50%, anchoring becomes mandatory before each new task unit.
• issue-lifecycle: Anchor checks confirm status transitions are warranted before the agent proposes them.