Response Optimization

Purpose

Design MCP tool responses that work for both humans (readable) and AI agents (parseable), with JSON flags for automation, token/ID systems for cross-tool references, and progressive detail levels based on relevance or confidence.

When to Use

Apply these patterns when:

• Responses need to be both human-readable and machine-parseable
• Tools generate data consumed by other tools
• Detail level should vary by relevance/confidence
• Automation needs status flags (has_more, truncated)
• Token efficiency is critical

Core Concepts

1. Human/LLM Readable Format

Design responses that serve both audiences:

Human needs:

• Scannable structure
• Clear labels
• Sparse tables for overview
• Narrative descriptions

LLM/AI needs:

• Structured JSON
• Consistent schemas
• Automation flags
• Parseable data

Example response:

{
  "results": [
    {"id": "r1", "name": "authenticate", "confidence": 0.95},
    {"id": "r2", "name": "authorize", "confidence": 0.75}
  ],
  "has_more": true,
  "total": 127,
  "truncated": false,
  "summary": "Found 127 matches, showing top 2. Use get_details(id) for more."
}

Human reads: "127 matches, top 2 shown, use get_details for more" AI parses: has_more: true, total: 127, result IDs for next tools

2. JSON Automation Flags

Standard flags that enable AI agents to understand response state:

Common flags:

Flag	Type	Purpose	Example
has_more	boolean	More results available	true
total	integer	Total matches found	127
truncated	boolean	Response was truncated	false
confidence	number	Result quality (0-1)	0.95
complete	boolean	Operation finished	true
partial	boolean	Partial results returned	false
estimated	boolean	Values are estimates	false

Example usage in responses:

{
  "results": [...],
  "metadata": {
    "has_more": true,
    "total": 1247,
    "returned": 10,
    "truncated": false,
    "complete": true,
    "query_time_ms": 4
  }
}

AI agent logic:

// Pseudocode
if (response.metadata.has_more) {
  // Offer to fetch more results
} else if (response.metadata.truncated) {
  // Warn user about truncation
} else {
  // This is everything
}

3. Token/ID Systems for Cross-Tool References

Use IDs instead of repeating data between tools:

Anti-pattern (wasteful):

// Tool 1: search
{
  "results": [
    {
      "name": "User.authenticate",
      "file": "/src/models/user.ts",
      "line": 42,
      "code": "async authenticate(password: string) {\n  // ... 50 lines ...\n}",
      "documentation": "... 200 words ..."
    }
  ]
}

// Tool 2: get_details
// User repeats entire context

Good pattern (efficient):

// Tool 1: search
{
  "results": [
    {
      "id": "def_a1b2",
      "name": "User.authenticate",
      "preview": "async authenticate(password: string)",
      "confidence": 0.95
    }
  ]
}

// Tool 2: get_definition
// Input: {id: "def_a1b2"}
// Returns full details

Token savings: ~80% reduction (50 tokens vs 250 tokens)

ID format patterns:

Short hash:     a1b2, c3d4, e5f6
Prefixed:       def_a1b2, ref_c3d4, sym_e5f6
Sequential:     result_1, result_2, result_3
UUID subset:    a1b2c3d4

Recommendation: Short hash (4-8 chars) with optional prefix for clarity

4. Progressive Detail by Relevance

Vary detail level based on match strength, confidence, or relevance:

Example: Search results with confidence-based detail

{
  "results": [
    {
      "id": "r1",
      "confidence": 0.95,
      "name": "User.authenticate",
      "type": "function",
      "file": "src/models/user.ts",
      "line": 42,
      "signature": "async authenticate(password: string): Promise<boolean>",
      "documentation": "Authenticates user with password",
      "preview": "Full code preview here..."
    },
    {
      "id": "r2",
      "confidence": 0.70,
      "name": "User.validate",
      "type": "function",
      "summary": "Basic validation method"
    },
    {
      "id": "r3",
      "confidence": 0.40,
      "name": "User.check"
    }
  ]
}

Detail levels:

• High confidence (>0.8): Full details (signature, docs, preview)
• Medium confidence (0.5-0.8): Summary only
• Low confidence (<0.5): Name + ID only (use get_details for more)

Token distribution:

• High: ~200 tokens each
• Medium: ~50 tokens each
• Low: ~10 tokens each

Benefits:

• Most relevant results get full attention
• Token budget focused on likely matches
• User can request details for any result

5. Sparse Tables + JSON Arrays

Provide both formats for different consumers:

Sparse table (human-friendly):

Results
=======

ID   | Name              | Type     | Confidence | File
---- | ----------------- | -------- | ---------- | ----
r1   | User.authenticate | function | 0.95       | user.ts
r2   | User.validate     | function | 0.70       | user.ts
r3   | User.check        | function | 0.40       | user.ts

Use get_definition(id) for full details

JSON array (machine-friendly):

{
  "results": [
    {"id": "r1", "name": "User.authenticate", "type": "function", "confidence": 0.95, "file": "user.ts"},
    {"id": "r2", "name": "User.validate", "type": "function", "confidence": 0.70, "file": "user.ts"},
    {"id": "r3", "name": "User.check", "type": "function", "confidence": 0.40, "file": "user.ts"}
  ],
  "has_more": false,
  "total": 3
}

When to use each:

• Sparse table: Info tools, overview outputs, human-focused
• JSON array: All programmatic outputs, AI agent consumption

Automation Flag Patterns

Pattern 1: Pagination Flags

{
  "results": [...],
  "pagination": {
    "has_more": true,
    "total": 1247,
    "returned": 10,
    "offset": 0,
    "limit": 10,
    "next_token": "eyJ..."  // Optional cursor
  }
}

Pattern 2: Completion Flags

{
  "status": "partial",
  "complete": false,
  "progress": 0.45,
  "estimated_completion": "2s",
  "results": [...],
  "continue_token": "abc123"
}

Pattern 3: Quality Flags

{
  "results": [...],
  "quality": {
    "confidence": 0.85,
    "estimated": false,
    "stale": false,
    "cached": true,
    "cache_age_seconds": 30
  }
}

Pattern 4: Error/Warning Flags

{
  "results": [...],
  "errors": [],
  "warnings": [
    "Unknown parameter 'foo' ignored",
    "Large result set, consider filtering"
  ],
  "partial_errors": false
}

Token/ID Relationship Patterns

Pattern 1: Single ID Type

search() → result_id[]
get_definition(result_id) → details

Simple, works for small MCPs (5-10 tools)

Pattern 2: Typed IDs

search() → result_id[] (prefixed: res_*)
get_definition(result_id) → symbol_id (prefixed: sym_*)
find_references(symbol_id) → reference_id[] (prefixed: ref_*)

Clear type distinction, works for 10-20 tools

Pattern 3: Hierarchical IDs

proxy_start() → proxy_id
currentpage(proxy_id) → session_id
proxylog(proxy_id, session_id) → request_id[]

Parent-child relationships, works for complex stateful MCPs

Progressive Detail Examples

Example 1: Code Search Results

Query: "authenticate"

Response with progressive detail:

{
  "results": [
    {
      "id": "a1b2",
      "confidence": 0.98,
      "full_detail": {
        "name": "User.authenticate",
        "type": "async function",
        "file": "src/models/user.ts",
        "line": 42,
        "signature": "async authenticate(password: string): Promise<boolean>",
        "documentation": "Authenticates user credentials against database",
        "preview": "async authenticate(password: string) {\n  const hash = await bcrypt.hash(password, this.salt)\n  return hash === this.passwordHash\n}"
      }
    },
    {
      "id": "c3d4",
      "confidence": 0.72,
      "summary": {
        "name": "AuthService.authenticate",
        "type": "function",
        "file": "src/services/auth.ts"
      }
    },
    {
      "id": "e5f6",
      "confidence": 0.45,
      "minimal": {
        "name": "validateAuth"
      }
    }
  ],
  "has_more": true,
  "total": 47,
  "note": "High confidence results show full details. Use get_definition(id) for others."
}

Example 2: Process Status

Progressive detail by request:

Level 1 - Overview:

{
  "active_processes": 5,
  "use": "list_processes for details"
}

Level 2 - List:

{
  "processes": [
    {"id": "p1", "name": "dev-server", "status": "running"},
    {"id": "p2", "name": "test-suite", "status": "running"}
  ]
}

Level 3 - Detail:

{
  "process": {
    "id": "p1",
    "name": "dev-server",
    "status": "running",
    "uptime": "2h 15m",
    "memory": "245MB",
    "cpu": "15%",
    "output_preview": "Server listening on :3000"
  }
}

Level 4 - Full:

{
  "process": {
    /* ... all Level 3 fields ... */,
    "full_output": "... complete logs ...",
    "env": {...},
    "metrics": {...}
  }
}

Accept Extra Parameters (Critical Pattern)

Always accept, warn, don't reject:

// Pseudocode
function search(params: any) {
  const {pattern, filter, max, ...extra} = params

  // Build response
  const results = performSearch(pattern, filter, max)

  // Warn about unknowns (don't fail)
  const warnings = []
  if (Object.keys(extra).length > 0) {
    warnings.push(`Unknown parameters ignored: ${Object.keys(extra).join(', ')}`)
  }

  return {
    results,
    warnings,
    has_more: results.length < total,
    total
  }
}

Why critical: AI agents hallucinate parameters. Be permissive unless severe issue (security, corruption).

Quick Reference

Response optimization checklist:

• Both human-readable and machine-parseable
• Automation flags included (has_more, total, etc.)
• ID system for cross-tool references
• Progressive detail by confidence/relevance
• Sparse tables for human, JSON arrays for machines
• Accept extra parameters with warnings
• Clear next steps for users
• Token-efficient design

Key patterns:

1. Dual format: Sparse tables + JSON arrays
2. Automation flags: Standard metadata for AI agents
3. ID references: Avoid repeating data between tools
4. Progressive detail: More detail for higher confidence
5. Permissive inputs: Accept and warn, don't reject

Focus on making responses useful for both humans reading them and AI agents processing them.