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/ychampion/cskill-agents/agent-specific-mcp-server-initializationnpx skills add ychampion/cskill-agents --skill agent-specific-mcp-server-initializationgit clone --depth 1 https://github.com/ychampion/cskill-agentsWrote 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/ychampion/cskill-agents/agent-specific-mcp-server-initialization)<a href="https://agentmods.dev/skills/ychampion/cskill-agents/agent-specific-mcp-server-initialization"><img src="https://agentmods.dev/badge/skills/ychampion/cskill-agents/agent-specific-mcp-server-initialization.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 | $0.00032 | $0.00405 |
| Opus 5 | $0.00016 | $0.00202 |
| Sonnet 5 | $0.00006 | $0.00081 |
| Haiku 4.5 | $0.00003 | $0.00040 |
Grade A, and why
agent-specific-mcp-server-initialization 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 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.
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
SKILL: Agent-Specific MCP Server Initialization
Domain: mcp-initialization Trigger: Load this skill when an agent defines extra MCP servers in its frontmatter and those clients must be joined to the parent session. Source Pattern: Distilled from reviewed subagent orchestration, isolation, and lifecycle implementations.
Core Method
Iterate the servers declared by the child agent, resolve named references from shared MCP configuration, and treat inline declarations as new agent-owned connections. Merge the resulting clients and tools into the inherited parent context, but keep track of which connections were created specifically for that child agent. When the agent ends, tear down only those agent-owned connections while leaving inherited shared clients intact. If no extra servers are declared, return the parent context unchanged.
Key Rules
- Short-circuit when the agent declares no extra MCP servers and return the inherited clients unchanged.
- For string specs, reuse memoized MCP configs; for inline objects, mark the resulting clients as newly created so their cleanup runs after the agent ends.
- Always return the merged client list plus the fetched tools, and expose a cleanup closure that only targets the newly created clients.
- Guard the loop with logging for missing configs so failures degrade gracefully instead of throwing.
Example Application
When implementing a custom agent that needs access to an inline MCP server, plug into this skill to merge the new server with the parent clients, reuse any shared configs, and ensure only the inline connection runs its cleanup path.
Anti-Patterns (What NOT to do)
- Don’t rebuild the entire MCP client list from scratch every turn; reuse the inherited parent clients and append the new ones instead.
- Don’t forget to clean up inline MCP servers; leaking them leaves dangling connections and stale credentials.
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 · 28 lines · 32 tokens per session scan A 04e677cc978a
agent-specific-mcp-server-initialization is a skill published in the GitHub repository ychampion/cskill-agents (36 stars, last pushed 5mo ago), licensed MIT. It adds 32 tokens to every session and 405 once invoked, about $0.0002 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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