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.
npx agentmods add agents/elvismusli/onlyharness/plan_readergit clone --depth 1 https://github.com/elvismusli/onlyharnessWhat 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 | $0.00000 | $0.00034 |
| Opus 5 | $0.00000 | $0.00017 |
| Sonnet 5 | $0.00000 | $0.00007 |
| Haiku 4.5 | $0.00000 | $0.00003 |
Grade A, and why
plan_reader 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 yesterday.
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.
The source is not reproduced here
No licence file
A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.
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.
- yesterday First seen · 7 lines · 0 tokens per session scan A 1513dd35e5f5
plan_reader is an agent published in the GitHub repository elvismusli/onlyharness (0 stars, last pushed 1mo ago), with no licence file. It costs nothing until one of its globs matches a file; then it loads 34 tokens. 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 2026-08-31.
Other agents, from other repositories
feature-reviewer
Engineering scrutiny subagent for a bounded validation-review question. Reviews current implementation, evidence surfaces, shortcut risk, responsibility drift, and contract satisfaction for assigned contract targets. Parent validator decides.
designer
Visual designer, UX/UI agent, and Open Design handoff producer.
speckit-constitution
Review or amend the project constitution. Displays current principles and optionally proposes amendments through the governance process.
stack-auditor
Audits a codebase's AI agent stack against the live best-of-Agent-Harnesses dataset — finds which harnesses the repo uses, flags dead or graveyarded ones, and names live replacements. Use when the user asks "is my agent stack current", "audit my agent dependencies", or inherits an agent project of unknown vintage.
evolution-runner
name: evolution-runner description: Dispatched automatically on session initialization, or triggered manually by the user. Uses the evolution-engine skill to scan feedback and generate evolution proposals. skills: evolution-engine model: opus color: purple.
prompt-forager
Context-starved prompt forager for diversity injection. Receives ONE line (a purpose) and deliberately nothing else, then searches external creativity-technique catalogs and prompt collections for 3-5 prompts from angles the requesting session would not produce itself. Dispatched by the prompt-perturb skill — not for…