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/m1rl0k/context-engine/mcp-tool-selectionnpx skills add m1rl0k/Context-Engine --skill mcp-tool-selectiongit clone --depth 1 https://github.com/m1rl0k/Context-EngineWrote 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/m1rl0k/context-engine/mcp-tool-selection)<a href="https://agentmods.dev/skills/m1rl0k/context-engine/mcp-tool-selection"><img src="https://agentmods.dev/badge/skills/m1rl0k/context-engine/mcp-tool-selection.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 | $0.00046 | $0.00444 |
| Opus 5 | $0.00023 | $0.00222 |
| Sonnet 5 | $0.00009 | $0.00089 |
| Haiku 4.5 | $0.00005 | $0.00044 |
Grade A, and why
mcp-tool-selection 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 3d 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.
What it actually says
MCP Tool Selection Rules
Core principle: MCP Qdrant-Indexer tools are primary for exploring code and history. Start with MCP for exploration, debugging, or "where/why" questions; use literal search/file-open only for narrow exact-literal lookups.
Use MCP Qdrant-Indexer When
- Exploring or don't know exact strings/symbols
- Need semantic or cross-file understanding (relationships, patterns, architecture)
- Want ranked results with surrounding context, not just line hits
- Asking conceptual/architectural or "where/why" behavior questions
- Need rich context/snippets around matches
Use Literal Search/File-Open Only When
- Know exact string/function/variable or error message
- Only need to confirm existence or file/line quickly (not to understand behavior)
Grep Anti-Patterns (DON'T)
grep -r "auth" . # → Use MCP: "authentication mechanisms"
grep -r "cache" . # → Use MCP: "caching strategies"
grep -r "error" . # → Use MCP: "error handling patterns"
grep -r "database" . # → Use MCP: "database operations"
Literal Search Patterns (DO)
grep -rn "UserAlreadyExists" . # Specific error class
grep -rn "def authenticate_user" . # Exact function name
grep -rn "REDIS_HOST" . # Exact environment variable
Quick Decision Heuristic
| Question Type | Tool |
|---|---|
| "Where is X implemented?" | MCP repo_search |
| "How does authentication work?" | MCP context_answer |
| "Does REDIS_HOST exist?" | Literal grep |
| "Why did behavior change?" | search_commits_for + change_history_for_path |
If in doubt → start with MCP
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.
- 3d ago First seen · 51 lines · 46 tokens per session scan A 41a783fe7c15
mcp-tool-selection is a skill published in the GitHub repository m1rl0k/Context-Engine (2 stars, last pushed 5mo ago), licensed MIT. It adds 46 tokens to every session and 444 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It comes from a forked repository.
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