Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/Intense-Visions/harness-engineeringWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/intense-visions/harness-engineering/harness-performance-guardian)<a href="https://agentmods.dev/agents/intense-visions/harness-engineering/harness-performance-guardian"><img src="https://agentmods.dev/badge/agents/intense-visions/harness-engineering/harness-performance-guardian.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00015 | $0.09028 |
| Opus 5 | $0.00008 | $0.04514 |
| Sonnet 5 | $0.00003 | $0.01806 |
| Haiku 4.5 | $0.00002 | $0.00903 |
Grade A, and why
harness-performance-guardian scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 789 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Role
Run structural complexity checks, coupling analysis, benchmark regression detection, and size budget enforcement on PRs and scheduled runs
Skills
- harness-perf
- harness-tdd
- harness-perf-tdd
Steps
- Run
harness check-perf(always) - Run
harness perf(always)
Methodology
Harness Perf
Performance enforcement and benchmark management. Tier-based gates block commits and merges based on complexity, coupling, and runtime regression severity.
When to Use
- After code changes to verify performance hasn't degraded
- On PRs to enforce performance budgets
- For periodic performance audits
- NOT for initial development (use harness-tdd for that)
- NOT for brainstorming performance improvements (use harness-brainstorming)
Process
Iron Law
No merge with Tier 1 performance violations. No commit with cyclomatic complexity exceeding the error threshold.
Tier 1 violations are non-negotiable blockers. If a Tier 1 violation is detected, execution halts and the violation must be resolved before any further progress. Do not attempt workarounds.
Phase 1: ANALYZE — Structural and Coupling Checks
-
Assess current performance posture. Run
check_performanceto evaluate current performance metrics against defined budgets. Runget_critical_pathsto identify performance-critical functions and hot paths. -
Run structural checks. Execute
harness check-perf --structuralto compute complexity metrics for all changed files:- Cyclomatic complexity per function
- Nesting depth per function
- File length (lines of code)
- Parameter count per function
-
Run coupling checks. Execute
harness check-perf --couplingto compute coupling metrics:- Fan-in and fan-out per module
- Afferent and efferent coupling
- Transitive dependency depth
- Circular dependency detection
-
Classify violations by tier:
- Tier 1 (error, block commit): Cyclomatic complexity > 15, circular dependencies, hotspot in top 5%
- Tier 2 (warning, block merge): Complexity > 10, nesting > 4, fan-out > 10, size budget exceeded
- Tier 3 (info, no gate): File length > 300, fan-in > 20, transitive depth > 30
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 7d ago First seen · 789 lines · 15 tokens per session scan A 6f29f835d043
harness-performance-guardian is an agent published in the GitHub repository Intense-Visions/harness-engineering (20 stars, last pushed today), licensed MIT. It adds 15 tokens to every session and 9,028 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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