| name | mcp-router |
| description | MCP 服务器自动按需加载技能。避免常驻 MCP 导致的 token 浪费。
每次对话开始时检测任务类型，只加载当前任务必需的 MCP 服务器。
复用 github.com/JuliusBrussee/caveman (shrink proxy) 和 github.com/rtk-ai/rtk (output filter) 策略。
|
| tags | ["mcp","token-optimization","performance"] |
MCP Router
Why
11 个 MCP 服务器常驻 = 每轮注入 ~11,000 tokens 的工具描述。按需求载可省 ~80% 的 MCP 注入开销。
Task → MCP Mapping
| Task Type | What you do | Load These MCPs | Est. tokens/turn |
|---|
| coding | Write/edit code, review PRs | token-savior, entroly, github | ~3,500 |
| research | Search papers, academic work | token-savior, entroly, semantic-scholar | ~3,000 |
| ui | Design review, generate images/diagrams | token-savior, entroly, ui-expert-mcp, image-generation, diagram-generator | ~5,500 |
| debug | Deep debugging, complex reasoning | token-savior, entroly, thinking | ~3,000 |
| docs | Write docs, web fetch | token-savior, entroly | ~2,000 |
| ops | Deploy, server ops | token-savior, entroly | ~2,000 |
| full | Need everything | All 11 (use .mcp.json.full) | ~11,000 |
Built-in alternatives — Prefer these over MCP servers to save tokens:
- File ops → Kimi
Shell/Glob/ReadFile (no MCP overhead)
- Web fetch → Kimi
WebFetch (no MCP overhead)
- Browser → Only use
puppeteer when screenshots needed
How to Use
1. Auto-detect on session start
At the start of every conversation, read .mcp.json and compare against the user's first request. If the loaded MCPs don't match the task type:
- State: "Current MCP set: [X, Y]. Task type: [coding]. Recommended: [X, Y, Z]."
- Ask: "Switch to [coding] profile?" (or auto-switch if user previously approved)
- Modify
.mcp.json → reload
2. Switch command
When user says any of these, trigger a profile switch:
| User says | Action |
|---|
| "查论文" / "search paper" / "semantic scholar" | Load semantic-scholar, unload others |
| "生成图片" / "image" / "diagram" | Load ui-expert-mcp + image-generation + diagram-generator |
| "调试" / "debug" / "think step by step" | Load thinking |
| "操作 GitHub" / "PR" / "issue" | Load github |
| "用全部 MCP" / "full mode" | Restore .mcp.json.full |
| "精简 MCP" / "minimal" | Keep only token-savior + entroly |
3. One-off usage (no profile switch)
If user only needs an MCP for a single query:
- Load it temporarily
- Execute the tool call
- Unload it immediately
This avoids paying the token cost for the rest of the conversation.
Configuration Files
| File | Purpose |
|---|
.mcp.json | Active config (2-3 MCPs max) |
.mcp.json.full | Full config (all 11 MCPs) |
.mcp.json.ondemand | Per-server snippets for manual copy |
mcp-servers/mcp-shrink.js | Shrink proxy (compresses tool descriptions, ~30% savings) |
scripts/rtk-filter.ps1 | RTK-style shell output filter (reduces tool output tokens) |
Token Budget Rules
- Input > 60K in one session → Start new session
- Tool output > 5K chars → Truncate or use
rtk-filter.ps1
- Session switching →
/compact before new task
- Never keep > 5 MCPs loaded simultaneously
Shrink Proxy
All MCP servers in .mcp.json and .mcp.json.ondemand are wrapped with mcp-servers/mcp-shrink.js.
This intercepts tools/list responses and compresses description fields using caveman rules:
- Removes filler: "This tool allows you to..." → ""
- Removes hedging: "likely", "probably", "generally" → ""
- Removes articles: "a", "an", "the" → ""
- Preserves code, URLs, paths, identifiers
Saves ~30% on MCP description tokens with zero semantic loss.
RTK Output Filter
For shell commands that produce long output, use scripts/rtk-filter.ps1:
# Instead of: git status (2,000 tokens)
# Use:
.\scripts\rtk-filter.ps1 git status # ~200 tokens
# Instead of: npm test (25,000 tokens on failure)
# Use:
.\scripts\rtk-filter.ps1 npm test # ~2,500 tokens
# Supports: git, npm, cargo, pytest, docker, kubectl, ls, cat, grep
Or manually apply RTK principles to any shell output:
- Filter: Strip progress bars, ASCII art, timestamps
- Group: Aggregate by file/type instead of listing every line
- Truncate:
Select-Object -First 50, add "... (N more)"
- Deduplicate: Collapse repeated lines with count
Verification
After any MCP profile switch, verify shrink proxy works:
- Check
.mcp.json uses "command": "node", "args": ["mcp-servers/mcp-shrink.js", ...]
- Run a tool call → descriptions should be terse
- If shrink fails, fall back to direct command (remove shrink wrapper)
Anti-patterns
❌ All 11 MCPs loaded for a simple code edit
❌ Loading MCPs preemptively "just in case"
❌ Forgetting to unload after one-off usage
❌ Using filesystem MCP when Kimi Shell/ReadFile works
❌ Using fetch MCP when Kimi WebFetch works
❌ Running npm test without rtk-filter.ps1 on large test suites
