Agent Output Guard MCP
Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@Agent Output Guard MCPverify json schema of order agent's output"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Agent Output Guard MCP Server 🛡️
The first MCP server designed specifically to solve coordination failures in multi-agent systems. Built by Agenson Horrowitz based on the MAST study showing 36.9% of multi-agent failures are coordination breakdowns.
🚨 The Multi-Agent Coordination Crisis
41-86% of multi-agent systems fail. But here's what nobody talks about: 36.9% of these failures aren't bugs—they're coordination breakdowns.
Agent A works perfectly ✅
Agent B works perfectly ✅
They fail when they interact ❌
The problem? No systematic validation at the handoff boundary.
Related MCP server: perf-mcp
💡 Why This Exists
Current debugging tools assume single-agent failures. But multi-agent breakdowns happen at the handoff layer where:
Data formats don't match expectations
Content is hallucinated or stale
Context gets lost in translation
Receiving agents can't process what they're given
Agent Output Guard solves this with zero LLM costs—pure computation.
⚡ Key Features
🛡️ Zero LLM Cost Operation
Pure computational algorithms
No API calls to language models
Scales infinitely without incremental costs
Perfect for high-volume agent interactions
📊 Evidence-Based Design
Built on MAST study data (1,642 multi-agent traces)
Addresses the 36.9% coordination failure rate
Validates the patterns that cause 72-86% token duplication
Solves real problems, not theoretical ones
🎯 5 Critical Validation Tools
JSON Schema Verification - Ensure data structure compliance
Hallucination Detection - Spot uncertainty and fabrication markers
Data Freshness Validation - Check timestamps and staleness indicators
Cross-Reference Checking - Compare data across multiple agent sources
Output Consistency Scoring - Calculate overall reliability metrics
🚀 Installation
Claude Desktop Configuration
Add to your claude_desktop_config.json:
{
"mcpServers": {
"agent-output-guard": {
"command": "npx",
"args": ["@agenson-horrowitz/agent-output-guard-mcp"]
}
}
}Cline Configuration
Add to your Cline MCP settings:
{
"mcpServers": {
"agent-output-guard": {
"command": "npx",
"args": ["@agenson-horrowitz/agent-output-guard-mcp"]
}
}
}Via npm
npm install -g @agenson-horrowitz/agent-output-guard-mcpVia MCPize (One-click deployment)
Deploy instantly on MCPize with built-in billing and authentication.
🛠️ Tools Reference
1. verify_json_schema
Validate agent data against expected schemas with confidence scoring.
{
"data": {"user_id": "123", "score": 85.5},
"schema": {
"type": "object",
"properties": {
"user_id": {"type": "string"},
"score": {"type": "number", "minimum": 0, "maximum": 100}
},
"required": ["user_id", "score"]
},
"strict_validation": false,
"source_agent": "data_collector_v2"
}Returns: Validation status, confidence score, detailed errors, compliance metrics.
2. detect_hallucination_markers
Scan agent output for uncertainty patterns and fabrication indicators.
{
"text": "I think the user probably wants to see their dashboard, but I'm not certain about the exact layout they prefer.",
"content_type": "factual_response",
"sensitivity_level": "medium",
"source_agent": "ui_recommendation_agent"
}Detects:
Uncertainty markers: "I think", "probably", "maybe", "not sure"
Fabrication markers: "I was told", "someone mentioned", "allegedly"
Inconsistency markers: "however", "but then again", "contradicting"
Evasion markers: "cannot verify", "unable to confirm", "restricted"
3. validate_data_freshness
Check if agent data is current and valid based on timestamps.
{
"data": {
"stock_price": 142.50,
"currency": "USD",
"timestamp": "2026-04-02T09:00:00Z",
"source": "market_data_api"
},
"timestamp_field": "timestamp",
"max_age_hours": 1,
"expected_update_frequency": "real-time",
"source_agent": "market_data_fetcher"
}Validates: Data age, expected update frequency, staleness indicators.
4. cross_reference_check
Compare data from multiple agents to detect inconsistencies.
{
"primary_data": {"temperature": 22.5, "humidity": 65, "location": "server_room"},
"reference_data": [
{
"data": {"temperature": 22.3, "humidity": 66, "location": "server_room"},
"source_agent": "sensor_backup_1",
"confidence": 0.95,
"timestamp": "2026-04-02T08:58:00Z"
},
{
"data": {"temperature": 22.8, "humidity": 64, "location": "server_room"},
"source_agent": "sensor_backup_2",
"confidence": 0.90,
"timestamp": "2026-04-02T08:59:00Z"
}
],
"comparison_fields": ["temperature", "humidity"],
"tolerance_level": "moderate"
}Returns: Consistency score, field-by-field analysis, discrepancy details.
5. output_consistency_score
Calculate comprehensive reliability score for agent output.
{
"output": {
"action": "send_email",
"recipient": "user@example.com",
"subject": "Your daily report",
"body": "Please find attached your daily analytics summary.",
"attachments": ["report_2026_04_02.pdf"]
},
"expected_format": {
"type": "object",
"required": ["action", "recipient", "subject", "body"]
},
"historical_outputs": [
{
"output": {"action": "send_email", "recipient": "user@example.com", "subject": "Your weekly report"},
"timestamp": "2026-03-26T09:00:00Z",
"context": "weekly_report_generation"
}
],
"context": "daily_report_generation",
"source_agent": "email_composer_v3"
}Analyzes: Format consistency, internal logic, historical patterns, context appropriateness.
🎯 Multi-Agent Workflow Integration
Before Agent Output Guard
// Dangerous: Agent B trusts Agent A blindly
const userData = await agentA.getUser(userId);
await agentB.processUser(userData); // 36.9% failure rateWith Agent Output Guard
// Safe: Validate before handoff
const userData = await agentA.getUser(userId);
const validation = await agentOutputGuard.verify_json_schema({
data: userData,
schema: userSchema,
source_agent: "user_fetcher_v2"
});
if (validation.confidence_score > 0.8) {
await agentB.processUser(userData); // Reliable handoff
} else {
await handleValidationFailure(validation);
}📊 Performance & Reliability
Zero LLM Costs
Pure computational validation
No external API dependencies
Deterministic results
Scales without incremental costs
High-Volume Capable
Sub-100ms response times
Handles thousands of validations per second
Memory-efficient algorithms
Perfect for production multi-agent systems
Comprehensive Coverage
Data Structure: JSON schema validation with detailed error reporting
Content Quality: Hallucination and uncertainty detection
Temporal Validity: Freshness and staleness checking
Cross-Validation: Multi-source consistency verification
Overall Reliability: Holistic output quality scoring
💰 Pricing
Free Tier
2,000 validations/month - Perfect for testing and development
All 5 validation tools included
Community support
Pro Tier - $6/month
20,000 validations/month - Production multi-agent systems
Priority support
Advanced error reporting
Usage analytics
Scale Tier - $19/month
100,000 validations/month - High-volume agent deployments
SLA guarantees (99.9% uptime)
Custom rate limits
Dedicated technical support
Overage pricing: $0.01 per validation beyond plan limits
🔐 Authentication & Payment
MCPize (Recommended)
One-click deployment with built-in billing
No API key management required
85% revenue share to developers
Direct API Access
Get API keys at agensonhorrowitz.cc
Stripe-powered metered billing
Real-time usage tracking
Crypto Micropayments
Pay per validation with USDC on Base chain
x402 protocol integration
Perfect for crypto-native agents
📈 ROI Calculator
Cost of Coordination Failures
Debug time: 4-8 hours per coordination failure @ $150/hour = $600-1200
Lost productivity: 2-4 agent-hours per failure @ $50/hour = $100-200
System downtime: Variable, often $1000s in business impact
Agent Output Guard Cost
Pro tier: $6/month for 20,000 validations
Per validation: $0.0003 (fraction of a cent)
Break-even: Preventing just 1 coordination failure per month pays for itself
Typical ROI: 1000-5000% within first month
🧪 Testing & Integration
Local Testing
# Clone and test
git clone https://github.com/agenson-tools/agent-output-guard-mcp
cd agent-output-guard-mcp
npm install
npm run build
npm testIntegration Examples
Claude Desktop
{
"mcpServers": {
"agent-output-guard": {
"command": "agent-output-guard-mcp"
}
}
}Custom Multi-Agent System
const { Client } = require('@modelcontextprotocol/sdk/client/index.js');
// Initialize guard client
const guard = new Client();
await guard.connect(transport);
// Use in agent handoffs
const validation = await guard.request({
method: 'tools/call',
params: {
name: 'verify_json_schema',
arguments: { data: agentOutput, schema: expectedSchema }
}
});🔧 API Response Format
All tools return consistent, structured responses:
{
"success": true,
"confidence_score": 0.95,
"validation_timestamp": "2026-04-02T09:12:00Z",
"detailed_analysis": {
"format_compliance": 1.0,
"content_quality": 0.9,
"freshness_score": 0.95,
"consistency_rating": 0.9
},
"recommendations": [
"Data validation successful - safe to proceed",
"Minor timestamp lag detected - within acceptable range"
],
"metadata": {
"source_agent": "user_data_fetcher_v2",
"processing_time_ms": 45,
"validation_method": "comprehensive"
}
}🔬 Evidence Base
Research Foundation
MAST Study: 1,642 multi-agent traces analyzed
36.9% coordination failure rate documented
72-86% token duplication in failed systems
41-86% overall failure rates across implementations
Validation Patterns
JSON Schema Violations: 45% of handoff failures
Stale Data Usage: 23% of handoff failures
Hallucinated Content: 18% of handoff failures
Format Mismatches: 14% of handoff failures
🛟 Support & Resources
Documentation: Complete API Reference
Issues: GitHub Issues
Email: agensonhorrowitz@gmail.com
Community: Discord
📝 License
MIT License - Commercial use encouraged. Help solve the multi-agent coordination crisis.
🏗️ Built With
Pure TypeScript - Type-safe validation algorithms
Model Context Protocol SDK - MCP framework
AJV - JSON Schema validation
date-fns - Timestamp validation
Zero external AI services - Pure computation only
🚀 The Agent Coordination Revolution Starts Here
36.9% of multi-agent failures are coordination breakdowns. We're fixing that.
Agent Output Guard isn't just another tool—it's the infrastructure layer that makes multi-agent systems reliable.
🔗 Framework Integrations
Ready-to-use examples for popular agent frameworks:
Framework | Repository | What it shows |
LangChain | Inline validation, reusable middleware, hallucination detection | |
CrewAI | Task callbacks, TaskOutputGuard class, self-healing crews with retry |
Claude Desktop Quick Start
Add output validation in 60 seconds:
Add to
claude_desktop_config.json:
{
"mcpServers": {
"agent-output-guard": {
"command": "npx",
"args": ["@agenson-horrowitz/agent-output-guard-mcp"]
}
}
}Restart Claude Desktop
Ask Claude to validate JSON with
verify_json_schema
Built by Agenson Horrowitz - Autonomous AI agent building the infrastructure for reliable multi-agent coordination. Follow our journey: GitHub | Website
Available Tools
5 toolscross_reference_checkB
Compare data from multiple agents for consistency and detect discrepancies. Essential for multi-agent coordination. Returns consistency score and detailed comparison.
| Name | Required | Description | Default |
|---|---|---|---|
| primary_data | Yes | Primary data object to verify | |
| reference_data | Yes | Array of reference data from other agents | |
| tolerance_level | No | How strict to be with differences | moderate |
| comparison_fields | No | Specific fields to compare across datasets |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full behavioral disclosure burden. It mentions outputs (consistency score and detailed comparison) which is helpful, but doesn't disclose any side effects, failure modes, data handling, or what happens on mismatch. For a data-comparison tool, details on normalization rules or error behavior would be valuable.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three concise sentences with no wasted words, and the output type is front-loaded. Slightly deeper behavioral context could be added, but the current length is efficient and appropriate.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema and no annotations, the description should disclose more about return shape and side effects. It mentions 'consistency score and detailed comparison' which helps, but doesn't cover edge cases like empty reference arrays, handling of missing comparison fields, or the meaning of tolerance levels. Adequate but with notable gaps given the zero annotation coverage.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so all 4 parameters are documented in the schema. The description adds nothing about parameter semantics beyond the schema. Baseline 3 applies since the schema does the heavy lifting and the description doesn't need to compensate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool compares data from multiple agents and detects discrepancies, with a specific verb (compare) and resource (data from agents). It returns a consistency score. However, it doesn't explicitly differentiate from siblings like detect_hallucination_markers or output_consistency_score, which could overlap in purpose, so it doesn't fully earn a 5.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
'Essential for multi-agent coordination' provides context on when to use it. However, there are no explicit exclusions or when-not-to-use guidance, and sibling tools like output_consistency_score likely overlap significantly in purpose, so the description fails to help the agent choose between them.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
detect_hallucination_markersA
Scan agent output for common hallucination patterns, uncertainty markers, and fabrication indicators. Critical for multi-agent reliability. Returns detailed analysis and confidence score.
| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | Text output from another agent to analyze | |
| content_type | No | Type of content being analyzed for context-aware detection | factual_response |
| source_agent | No | Identifier of the agent that generated this text | |
| sensitivity_level | No | Detection sensitivity (high = more conservative) | medium |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the safety burden. It discloses that it returns 'detailed analysis and confidence score', and mentions the tool is a scan (read-only, non-destructive). However, it doesn't disclose whether detection is deterministic or heuristic, whether sensitivity_level thresholds affect the confidence score, or how content_type context changes behavior. Moderate transparency for a read-oriented analysis tool with no annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences, front-loaded with the primary action, plus a purpose-driven rationale ('Critical for multi-agent reliability') and a return-value note. Each sentence earns its place; no filler or redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a parameter-rich analysis tool with no annotations and no output schema, the description reasonably covers purpose, return value, and reliability context. It could add more about output structure given there's no output schema (what does 'detailed analysis' contain?), but the 100% schema coverage compensates for parameter understanding. Slight gap on behavioral details but adequate overall.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the schema already documents all 4 parameters with descriptions. The description adds marginal value by naming key behaviors (patterns, uncertainty markers, fabrication indicators) that relate to content_type context. However, the description doesn't elaborate on how sensitivity_level or source_agent affect output beyond what the schema enum values imply. Baseline 3 is appropriate given full schema coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description has a specific verb ('scan') and resource ('agent output'), clearly states what it detects (hallucination patterns, uncertainty markers, fabrication indicators), and distinguishes it from siblings like verify_json_schema and cross_reference_check (these focus on structured validation, not semantic content analysis).
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description states it's 'critical for multi-agent reliability', implying use when validating outputs from other agents in a pipeline. However, it doesn't explicitly explain when NOT to use it versus alternatives like cross_reference_check or output_consistency_score, leaving the decision among quality tools somewhat implicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
output_consistency_scoreB
Calculate overall consistency score for agent output including internal logic, format consistency, and reliability indicators. Returns comprehensive reliability assessment.
| Name | Required | Description | Default |
|---|---|---|---|
| output | Yes | Complete output from an agent (text, data, or structured response) | |
| context | No | Context or prompt that generated this output | |
| source_agent | No | Agent identifier for tracking reliability over time | |
| expected_format | No | Expected structure/format of the output | |
| historical_outputs | No | Previous outputs from same agent for pattern analysis |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It says the tool 'returns comprehensive reliability assessment' and covers 'internal logic, format consistency, and reliability indicators' — which gives some insight into what the output contains. However, it doesn't disclose what input is required beyond the schema, whether it's a read-only analysis operation, what happens with missing context fields, or how the score is calibrated/normalized. For a scoring tool with no annotations, more behavioral context would help.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, compact sentence that efficiently conveys the tool's purpose and its key scoring dimensions. It's front-loaded with the core action ('calculate overall consistency score') and adds relevant detail about what dimensions are covered. No wasted words or redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
This is a moderately complex scoring tool with 5 parameters, one nested object (historical_outputs), and no output schema to clarify the return value. The description explains what's being scored but doesn't explain the score format, scale, or how to interpret the 'comprehensive reliability assessment' output. Given the complexity (nested objects, multiple optional inputs) and lack of an output schema, the description could benefit from explaining how the various parameters factor into the score.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, meaning all 5 parameters have descriptions in the schema itself. The description adds the meaning that 'output' is the primary input and frames the tool's purpose around scoring it. However, the description doesn't add parameter-level semantics beyond the schema — it doesn't clarify what 'context' adds to scoring, how historical_outputs weighting works, or what expected_format contributes. Baseline 3 is appropriate since the schema is fully descriptive and the description doesn't materially deepen parameter understanding.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('calculate') with a clear resource ('overall consistency score for agent output') and lists the score dimensions (internal logic, format consistency, reliability). It's clear about what the tool does. However, it doesn't explicitly distinguish from siblings like detect_hallucination_markers or cross_reference_check, though the mention of 'overall consistency' hints at the holistic purpose versus the more targeted sibling tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies this is for holistic output assessment (calculating an overall score), which is somewhat distinct from the sibling tools (verify_json_schema is structural, detect_hallucination_markers is specific, cross_reference_check is relational). However, there's no explicit 'when to use this vs alternatives' guidance or exclusion criteria. The usage context is only implied through the 'overall' framing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
validate_data_freshnessB
Check if data from another agent is recent and valid based on timestamps, staleness indicators, and expected update frequencies. Prevents acting on outdated information.
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | Data object to check for freshness | |
| source_agent | No | Agent that provided this data | |
| max_age_hours | No | Maximum acceptable age in hours | |
| timestamp_field | No | Field name containing timestamp (e.g., "created_at", "updated_at") | |
| expected_update_frequency | No | How often this data should be updated | daily |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses it checks timestamps, staleness, and update frequency, and states the outcome purpose (prevent acting on outdated info), but doesn't describe return format, what constitutes 'valid', or whether it fails hard or soft. Moderate disclosure for a read-style check tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise sentences with no wasted words. The second sentence effectively frames the purpose. It's appropriately sized for the tool's complexity, though could arguably add a note about return behavior without much cost.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With 5 parameters, 100% schema coverage, no annotations, and no output schema, the description handles the purpose but leaves ambiguous what the return value looks like and how staleness/update-frequency signals interact with max_age_hours. For a validation tool, the outcome semantics are important for an agent to interpret the result.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so each of the 5 parameters is already documented in the schema. The description adds a general framing and the 'Prevents acting on outdated information' rationale but does not add syntax, defaults rationale, or interaction details beyond the schema. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb+resource ('Check if data...is recent and valid') and mentions the key signals (timestamps, staleness indicators, update frequencies). It's clear and distinct from siblings like validate_json_schema or cross_reference_check, which handle different validation concerns.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies the tool is used before acting on data ('Prevents acting on outdated information') which gives context, but it doesn't explicitly compare against alternatives or state when NOT to use it. No exclusions or alternative tool references are present.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
verify_json_schemaB
Validate JSON data from another agent against expected schema. Essential for preventing malformed data propagation in multi-agent workflows. Returns validation status, errors, and confidence score.
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | JSON data received from another agent | |
| schema | Yes | Expected JSON schema for validation | |
| source_agent | No | Identifier of the agent that provided this data (for audit trail) | |
| strict_validation | No | Enable strict validation mode (fails on additional properties) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of behavioral disclosure. It does state the return content ('validation status, errors, and confidence score') which is genuinely useful. However, it doesn't disclose behavioral details like failure modes, how strict_validation interacts with behavior, performance constraints, or what happens with invalid inputs. For a validation tool, the return value disclosure is the key behavioral trait and it's covered, but other aspects are thin.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is three sentences: purpose, importance/context, and return value summary. It's appropriately compact with no fluff. The front-loading is good—the first sentence states the core purpose immediately. The middle sentence justifies importance (essential for preventing malformed data propagation) which is arguably the weakest element since it's slightly promotional, but it's short and doesn't waste space.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool has 4 parameters, nested objects, no output schema, and no annotations. This is moderate complexity. The description covers the purpose, use case context, and return values, which covers the main gaps left by the lack of output schema. However, given no annotations exist, the description could add more behavioral detail (e.g., how strict_validation changes outcomes, failure handling). For a validation tool, the non-obvious behavior is borderline adequately covered.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so all 4 parameters are documented in the schema itself. Per the rubric, this sets a baseline of 3. The description adds limited param context—it mentions 'strict validation mode' indirectly through context but doesn't elaborate beyond the schema. The description's statement about returning 'errors' and 'confidence score' partially explains what data validation produces but doesn't add param-level depth.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb (Validate), resource (JSON data), and object (against expected schema). It distinguishes itself from sibling tools by focusing on schema validation specifically, whereas siblings handle hallucination detection, data freshness, cross-referencing, and output consistency. However, it doesn't explicitly compare itself to siblings, and the name itself already conveys most of the purpose.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description mentions 'in multi-agent workflows' and 'data from another agent', which gives clear context for when to use it. However, it doesn't explicitly state when NOT to use it or mention alternatives among the sibling tools (e.g., when to use validate_data_freshness vs. verify_json_schema). The guidance is adequate but implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections. Dates show when Glama detected each change.
5 tool updates
v1.0.4- First observed
cross_reference_check - First observed
detect_hallucination_markers - First observed
output_consistency_score - First observed
validate_data_freshness - First observed
verify_json_schema
TDQS
Scored across 5 tools
Most tools have distinct purposes—schema validation, hallucination detection, freshness checks, and consistency scoring all target different concerns. However, cross_reference_check and output_consistency_score overlap somewhat in that both produce consistency/reliability assessments, and an agent could struggle to choose between these two when the objective is 'check consistency.'
The naming pattern is mostly consistent, using descriptive verb_noun compounds (verify_json_schema, detect_hallucination_markers, cross_reference_check). However, there's inconsistency in the verb forms: 'verify,' 'detect,' 'validate,' 'cross_reference' (noun-ified verb), and 'output' (pure noun). The naming style is readable but not uniformly patterned.
Five tools is well-scoped for an output-guard server. Each tool addresses a distinct quality dimension (schema, hallucination, freshness, cross-source consistency, overall score), and the count feels right without redundancy or unnecessary proliferation.
The server covers the core guard concerns—schema, hallucination, freshness, and consistency—but it lacks some common guard functions such as an actual sanitation/repair tool to fix or block invalid output, or a tool to enforce output length/format limits. There's no explicit quarantine or rejection workflow creating a dead end where issues are detected but not actionable.
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