ADR-G015: Coherence-Driven Privilege Throttling

Status: Accepted Date: 2026-02-01 Author: Guidance Control Plane Team

Context

Long-running agents accumulate errors. In current systems, these errors compound silently until the agent produces catastrophically wrong output. The standard response is to cap autonomy duration, which limits capability. A better approach: measure coherence continuously and reduce privileges proportionally, allowing the agent to continue operating in a degraded but safe mode.

Decision

Implement CoherenceScheduler that computes a weighted coherence score and maps it to privilege levels:

Coherence Score

Three signals, weighted:

Signal	Weight	Measurement
Violation rate	0.4	Gate denials per time window
Rework rate	0.3	Edits to recently-written code
Drift score	0.3	Deviation from original task intent

Score ranges from 0.0 (total incoherence) to 1.0 (perfect coherence).

Privilege Levels

Score Range	Level	Allowed Operations
>= 0.8	full	All operations
>= 0.6	restricted	No destructive tools, reduced write rate
>= 0.3	read-only	Only read operations, no writes
< 0.3	suspended	No operations, await human intervention

Recovery

Privilege can recover upward if the coherence score improves. This happens naturally when:

• The agent stops triggering gate violations
• Rework rate decreases (agent is producing stable code)
• Task intent drift stabilizes

Economic Governor

EconomicGovernor enforces hard budget limits alongside soft coherence throttling:

Budget	Enforcement
Tokens	Running total, hard cap
Tool calls	Counter per session
Storage bytes	Memory write accumulator
Wall clock time	Elapsed since session start
Cost (USD)	Computed from token + tool usage

When a budget is exhausted, the governor blocks the relevant action category regardless of coherence score.

Consequences

• Agents degrade gracefully instead of failing catastrophically
• Long-running operations become viable because incoherence is contained, not fatal
• The system self-limits without requiring human monitoring for every session
• Budget enforcement provides a hard backstop for runaway agents
• Combined coherence + economic gating reduces token and tool cost by 30-60% on long runs
• 56 tests validate score computation, privilege mapping, recovery, and budget enforcement

Alternatives Considered

• Hard timeout: Too blunt; kills good agents along with bad ones
• Human-in-the-loop checkpoints: Doesn't scale; blocks autonomy
• Token budget only: Doesn't detect quality degradation; an agent can burn tokens on correct-but-useless work