Open Jev Bridge

system_one_belay

Read-onlyIdempotent

Check transcripts for unsupported completion claims and return an advisory stop-hook decision to prevent premature completion.

Instructions

Judge whether a supplied transcript makes unsupported completion claims. Returns an advisory Stop-hook decision; runs no commands.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "messages": "<messages>"
    },
    "name": "system_one_belay"
  }
}

Input Schema

Name	Required	Description	Default
`messages`	Yes
`final_message`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Sep 23, 2026

TDQS

B3.3/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable context: it returns an 'advisory Stop-hook decision' and explicitly says it 'runs no commands', which clarifies its non-execution nature. This goes beyond the annotations without contradicting them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no wasted words. It front-loads the purpose and includes the key behavioral note (advisory, runs no commands). It is concise and well-structured for a tool of this complexity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

While the purpose and non-execution behavior are clear, the description omits any detail about the input parameters (especially 'final_message') and the exact structure of the advisory decision. Since there is no output schema and no parameter descriptions in the schema, the description should explain what an agent needs to supply and what it will receive. It does not, making the tool incomplete for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters1/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema description coverage is 0%, so the description must compensate by explaining the parameters. It does not. The description only says 'supplied transcript', which vaguely maps to the 'messages' array but does not clarify the role of 'final_message'. An agent cannot infer the meaning or format of these parameters from the description, leaving a significant gap for a tool with only two parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Judge') and a specific resource ('supplied transcript') with a clear purpose ('makes unsupported completion claims'). It also notes the return is an 'advisory Stop-hook decision' and that it 'runs no commands', which helps set it apart from some sibling tools. However, it does not explicitly distinguish itself from the many system_one_* siblings, so it loses a point for lacking differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage (judging completion claims in a transcript) but provides no explicit when-to-use guidance or alternatives. Given the large sibling set (system_one_gate, system_one_review, system_one_verify, etc.), it does not state when this tool is preferred over others. The purpose is clear enough to infer a use case, but it does not actively guide the agent toward this tool vs. alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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