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

Goes well past the annotations: it explains the response contract (valid is false exactly when fields is non-empty; fields lists ALL blocking findings, not just the first; warnings never block) and states the auth requirement (works with mcp:read tokens). These are exactly the traits an agent cannot infer from readOnlyHint/idempotentHint alone.

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 with the core action and tightly packed with the return semantics and usage rule. There is minor redundancy: 'a pure read, no side effects' largely restates the readOnlyHint/destructiveHint annotations, though the mcp:read token note in the same sentence adds new information.

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?

Given an output schema exists, the description could have stopped at purpose, yet it still clarifies how to interpret the returned fields — the highest-value ambiguity for a validation tool. Nothing needed to invoke it correctly is missing.

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 both parameters (type, config) are already documented with examples in the schema. The description adds the context that config is typically assembled by hand or adapted from a sample, but no format or syntax detail beyond the schema — the 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?

States a specific verb+resource ('Dry-run validate a check config') plus its scope ('without creating or changing anything'), which cleanly separates it from create_check/update_check in the sibling list. An agent can identify it without opening the 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?

Explicitly names the moment to use it ('before create_check when you've assembled a config from scratch or modified a sample') and names the sibling it precedes. The only mild gap is not naming update_check as a second caller, but the routing signal is unambiguous.

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