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

Annotations provide idempotentHint=true and destructiveHint=false, but the description adds significant behavioral detail: it makes no network call, is 'metered like scan_artifact' (indicating a cost), and detects specific threat types (tool poisoning, hidden directives, etc.). It also warns that it applies the same rules as scan_mcp_server, preventing false assurance. 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.

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

The description is compact and front-loaded: first states the core purpose, then the rationale, then the input format, then the analysis scope and metering. Every sentence adds value, though it packs a lot of information into five sentences. It could be slightly more terse, but the structured flow makes it easy to parse.

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 single-parameter tool with an output schema, the description covers everything needed: the input format, the local-only behavior, the detection capabilities, the metering, and the relationship to scan_mcp_server. No crucial information is missing, and the output schema handles return values.

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 the schema already documents the parameter thoroughly. The description's mention of 'a whole tools/list response, a {...} object, or a bare array' exactly mirrors the schema text, adding no new information. Baseline 3 applies because the schema carries the full semantic load.

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 starts with a clear verb and resource: 'Check tool definitions you ALREADY HOLD, with no network call to anyone.' It explicitly distinguishes from scan_mcp_server by noting it analyzes the same text but requires no network, making the tool's unique scope obvious.

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 explains when to use this tool: when you already have the tool definitions locally and cannot reach the server over the network ('Most MCP servers run locally over stdio and have no endpoint... this is the only way to check them'). It also references scan_mcp_server as the counterpart, implying that server is used when network access is possible. It doesn't explicitly state 'use scan_mcp_server for network scanning,' but the context makes it clear.

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