SigNoz MCP Context Optimization: Implementing Tool Filtering and Search

Session Date: 2026-01-19 Project: Claude Code Configuration (~/.claude) Focus: Minimize SigNoz MCP context/token usage in Claude Code Session Type: Research and Implementation

Executive Summary

Successfully researched and implemented multiple strategies to reduce SigNoz MCP server context usage in Claude Code. The SigNoz MCP provides 26 tools consuming an estimated 15,000-20,000 tokens at session start. Through implementing mcp-filter proxy filtering and enabling aggressive tool search thresholds, achieved an estimated 85%+ reduction in context consumption.

The solution involved installing mcp-filter as a proxy wrapper around the SigNoz MCP server, blocking the three heaviest tools (signoz_create_dashboard, signoz_update_dashboard, signoz_execute_builder_query) which alone account for ~11,500 tokens. Combined with ENABLE_TOOL_SEARCH=auto:5, tools are now loaded on-demand rather than preloaded.

Problem Statement

The SigNoz MCP server was contributing significant context overhead to Claude Code sessions:

Large Tool Schemas: Dashboard creation/update tools have deeply nested widget schemas (~5,000+ tokens each)
Preloaded Definitions: All 26 tools loaded at session start regardless of need
Verbose Responses: MCP tool outputs could consume excessive context

Impact Before: ~20,000 tokens consumed by SigNoz MCP alone at session initialization.

Research Phase

Agent Selection Journey

Initially attempted to use lead-research-assistant agent, which didn’t exist in the available agents. After installing the skill from the awesome-claude-skills marketplace, discovered it was designed for sales lead generation, not technical research.

Resolution: Used webscraping-research-analyst agent for comprehensive technical research on MCP context optimization strategies.

Key Research Findings

1. MCP Tool Search (Built-in Solution)

Enabled by default as of January 2026
Dynamically loads tools on-demand via MCPSearch
Achieves 85% reduction when tools exceed threshold
Configurable threshold: ENABLE_TOOL_SEARCH=auto:N where N is percentage

2. Third-Party Proxy Tools

Tool	Description	Token Reduction
mcp-filter	Python-based proxy with allow/deny patterns	72-91%
mcproxy	Node.js proxy with auto-config generation	Variable
Portkey filter	Semantic embedding-based selection	Variable

3. SigNoz Tool Analysis

Category	Tools	Schema Size
Metrics	4	Low (~150-200 tokens each)
Alerts	3	Low-Medium
Dashboards	4	Very High (~5,000+ for create/update)
Services	2	Medium
Logs	7	Low-Medium
Traces	6	Medium-High
Query Builder	1	High (~1,500 tokens)

4. Feature Request Status

Native tool filtering (Issue #7328) has 182+ upvotes, assigned but not yet implemented
Proxy-based filtering is the current community workaround

Implementation Details

Phase 1: Install mcp-filter

Command:

pip install mcp-filter

Installed Dependencies: mcp-filter 0.1.0 with fastmcp, mcp, and related packages.

Phase 2: Update MCP Configuration

File: ~/.claude/.mcp.json

Before:

{
  "mcpServers": {
    "signoz": {
      "command": "/Users/alyshialedlie/.claude/mcp-servers/signoz-mcp-server/bin/signoz-mcp-server",
      "args": [],
      "env": {
        "SIGNOZ_URL": "https://tight-ladybird.us.signoz.cloud",
        "SIGNOZ_API_KEY": "${SIGNOZ_API_KEY}",
        "LOG_LEVEL": "info",
        "GOMEMLIMIT": "50MiB",
        "GOGC": "50"
      }
    }
  }
}

After:

{
  "mcpServers": {
    "signoz": {
      "command": "mcp-filter",
      "args": [
        "run",
        "-t", "stdio",
        "--stdio-command", "/Users/alyshialedlie/.claude/mcp-servers/signoz-mcp-server/bin/signoz-mcp-server",
        "--deny-pattern", "signoz_(create|update)_dashboard",
        "--deny-pattern", "signoz_execute_builder_query",
        "--log-level", "WARNING"
      ],
      "env": {
        "SIGNOZ_URL": "https://tight-ladybird.us.signoz.cloud",
        "SIGNOZ_API_KEY": "${SIGNOZ_API_KEY}",
        "LOG_LEVEL": "info",
        "GOMEMLIMIT": "50MiB",
        "GOGC": "50"
      }
    }
  }
}

Design Decisions:

Deny patterns over allow lists: More maintainable as new tools are added
Regex patterns: signoz_(create|update)_dashboard catches both in one pattern
Log level WARNING: Reduces noise while preserving important messages

Phase 3: Enable Tool Search and Output Limits

File: ~/.claude/config/settings.json

Added Configuration:

{
  "env": {
    "ENABLE_TOOL_SEARCH": "auto:5",
    "MAX_MCP_OUTPUT_TOKENS": "15000"
  }
}

Rationale:

auto:5: Triggers tool search when MCP tools exceed 5% of context (more aggressive than default 10%)
MAX_MCP_OUTPUT_TOKENS=15000: Prevents verbose tool responses from consuming excessive context

Phase 4: Cleanup

Disabled lead-research-assistant@awesome-claude-skills plugin
Removed skill from skill-rules.json
Deleted skill folder from ~/.claude/skills/

Key Decisions and Trade-offs

Decision 1: mcp-filter vs mcproxy

Choice: mcp-filter (Python-based) Rationale: Simpler CLI interface, regex-based patterns, well-documented Alternative Considered: mcproxy (Node.js), rejected due to additional config file requirement Trade-off: Python dependency vs Node.js dependency (Python already available)

Decision 2: Deny Patterns vs Allow List

Choice: Deny patterns blocking 3 heavy tools Rationale: Future-proof as new SigNoz tools are added; only blocks known heavy tools Alternative Considered: Allow list of ~10 essential tools Trade-off: Less aggressive filtering, but more maintainable

Decision 3: Tool Search Threshold

Choice: 5% threshold (aggressive) Rationale: Maximizes context savings; SigNoz tools alone likely exceed 5% Alternative Considered: Default 10% Trade-off: Slightly slower tool discovery for maximum context savings

Tools Blocked

Tool	Estimated Tokens	Reason
`signoz_create_dashboard`	~5,000+	Deeply nested widget/query schemas
`signoz_update_dashboard`	~5,000+	Same as create
`signoz_execute_builder_query`	~1,500	Complex query structure
Total Blocked	~11,500

Tools Retained (23)

All other SigNoz tools remain available:

signoz_list_services, signoz_list_alerts, signoz_get_alert
signoz_get_error_logs, signoz_search_logs_by_service
signoz_search_traces_by_service, signoz_get_trace_details
signoz_list_dashboards, signoz_get_dashboard
And 14 more utility/query tools

Verification

Configuration Validation

$ npm run validate
✓ skill-rules.json is valid JSON
✓ All 21 skills have matching SKILL.md files and triggers
✓ settings.json is valid JSON
✓ All checks passed!

JSON Validation

$ cat .mcp.json | python3 -c "import json,sys; json.load(sys.stdin)"
✓ .mcp.json is valid JSON

Files Modified

Modified Files

Deleted Files

Note on .mcp.json

The .mcp.json file is gitignored and changes remain local-only. This is appropriate as the file may contain environment-specific paths.

Git Commits

Commit	Description
`22b1db4`	perf(mcp): add tool search and output limits for context optimization

Expected Performance Impact

Scenario	Before	After	Improvement
Initial Context Load	~20,000 tokens	~3,000-5,000 tokens	75-85%
With Tool Search Active	~20,000 tokens	~500 tokens	97%+
Dashboard Operations	Available	Blocked	N/A

Limitations

Dashboard Creation Blocked: Cannot create/update dashboards via MCP (must use SigNoz UI)
Query Builder Blocked: Complex queries must use specific tools or UI
Native Filtering Unavailable: Still waiting on Claude Code Issue #7328 for built-in solution

Next Steps

Immediate

✅ Restart Claude Code to apply changes
Use /context command to verify token reduction

If Dashboard Access Needed

Temporarily modify .mcp.json to remove deny patterns
Or use SigNoz web UI directly

Future Improvements

Monitor Issue #7328 for native tool filtering
Consider creating SigNoz guidance skill for tool selection

References

Code Files

~/.claude/.mcp.json - MCP server configuration
~/.claude/config/settings.json - Claude Code settings
~/.claude/config/skill-rules.json - Skill triggers

External Resources

Research Agents Used

general-purpose - Initial MCP configuration research
webscraping-research-analyst - Comprehensive optimization strategy research

context-optimization, mcp, mcp-filter, observability, python, signoz, tool-search

claude-code, mcp-configuration, performance-optimization

was published on January 19, 2026.