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 skills/eai-org/agent-toolkit/context-checkupnpx skills add eai-org/agent-toolkit --skill context-checkupgit clone --depth 1 https://github.com/eai-org/agent-toolkitWrote 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/skills/eai-org/agent-toolkit/context-checkup)<a href="https://agentmods.dev/skills/eai-org/agent-toolkit/context-checkup"><img src="https://agentmods.dev/badge/skills/eai-org/agent-toolkit/context-checkup.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 | $0.00027 | $0.00854 |
| Opus 5 | $0.00014 | $0.00427 |
| Sonnet 5 | $0.00005 | $0.00171 |
| Haiku 4.5 | $0.00003 | $0.00085 |
Grade A, and why
context-checkup scanned grade A with 2 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 4d 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.
Reads agent configuration directorieslowAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
cat .mcp.json; cat .claude/settings.json .claude/settings.local.json ~/.claude/settings.json 2>/dev/null Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Reads MCP configurationlowAgent snooping
mcp.json carries server URLs and auth tokens; reading it lets a mod discover and abuse other integrations.
cat .mcp.json; cat .claude/settings.json .claude/settings.local.json ~/.claude/settings.json 2>/dev/null Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Context checkup
Find what loads automatically into the session's context at startup, quantify it, and propose reversible trims ranked by payoff — shrink the startup context window by cutting what isn't worth its tokens. Read-only — measure and recommend; change settings only on explicit approval.
Mental model (spend attention top-down)
Cost hierarchy, biggest first:
- MCP tool schemas — large, but deferred by tool search. Only a problem if tool search is OFF.
- Always-on text — CLAUDE.md/AGENTS.md chain,
@imports, and skill/agent/command descriptions (every available one's description loads every session). - MCP server instructions — load per enabled server at startup; a chatty preamble can dwarf its tool names.
- MCP tool names — ~10 tokens each. Cheap; 30 names ≈ 300 tokens isn't worth a recommendation.
Rules: measure, never guess — wc/count, then attach a rough token figure to each finding.
Rank by tokens-saved × reversibility. Distinguish auto-loaded from lazy-linked (nested
AGENTS.md referenced from a parent are not loaded — don't flag them).
Tool-name counts, the skills/agents/commands lists, and tool-search status come from the session's system-reminders, not disk — read them from your own context.
Checklist
0. Verify tool search is on first. If ENABLE_TOOL_SEARCH is disabled, MCP schemas load eagerly
and every "names are cheap" conclusion flips. Check this before anything else.
1. Always-on docs. Measure the CLAUDE.md/AGENTS.md chain: project file + every parent dir up
to root + global ~/.claude/CLAUDE.md. Expand @import lines (recursive). wc -w each.
2. Descriptions (often the largest unexamined chunk). Skim the in-session lists of skills, subagent types, and slash commands — their descriptions are always loaded. Many rarely-used entries = standing cost.
3. MCP servers. From .mcp.json + settings, list enabled servers. Count tool names per
server; note any server with long instructions. Flag servers irrelevant to the user's work.
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.
- 4d ago First seen · 72 lines · 27 tokens per session scan A 3c8aa73af787
context-checkup is a skill published in the GitHub repository eai-org/agent-toolkit (43 stars, last pushed today), licensed MIT. It adds 27 tokens to every session and 854 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 2 findings (reads agent configuration directories, reads mcp configuration). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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