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

Annotations only declare readOnlyHint=false, openWorldHint=true, destructiveHint=false; the description explains WHY it is not read-only (unknown tools get queued and measured in ~10-20 minutes), gives the latency/queue timing, and adds the crucial interpretive caveat that 'Not measured' never means 'bad'. That is real context beyond the structured hints.

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?

Front-loaded payload list, then when/when-not, then an example — every line earns its place. No filler sentences and no repetition of the title.

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?

No output schema exists, yet the description enumerates the returned fields (verdict, success rate, consecutive successes, latency, last 20 checks), the async timing for unknown tools, and the semantic caveat about unmeasured results. An agent has everything needed to call and interpret it.

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% and both parameters (id, url) are self-documenting, so the baseline is 3. The description adds a working invocation example ({"url":"https://example.com/mcp"}) plus the framing 'by catalog id or public MCP URL', which clarifies the mutually-exclusive choice beyond the schema text.

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?

States a specific verb+resource ('independent measurements for ONE tool') and enumerates exactly what the verdict contains: success rate, consecutive successes, latency, last 20 checks. It also names the sibling it is not (solve_need), so an agent can route correctly without opening either schema.

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?

Explicit 'Use when' (you already know which tool and want to know if it works now) and 'Do not use when' (you are still looking for a tool, use solve_need) clauses name both the condition and the alternative tool. Nothing is left to inference.

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