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

Annotations already declare read-only, idempotent, non-destructive, closed-world, but the description adds operational context the annotations cannot: 32 KB payload ceiling, 60 RPM rate limit, L402 payment (75 sats) or ?demo=true fallback, and an HTTP 400 failure mode for invalid input. These are exactly the non-safety behavioral traits an agent needs before invoking.

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-loads purpose, then usage, then the alternative, then operational constraints — a sensible order with no filler sentences. It is dense and packed into few sentences, which slightly hurts readability, but every clause carries distinct 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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. The description fills the remaining gaps (cost/payment, rate limit, size limit, error behavior, sibling disambiguation), leaving nothing an agent needs in order to call it correctly.

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 contract_format, baseline_schema_json, and candidate_schema_json, establishing the baseline of 3. The description restates the baseline parameter name and adds a cryptic note about 'enum defaults' but does not clarify format expectations, size handling, or how auto_detect resolves — so it adds little beyond the schema.

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 (compares/detects) and precise resources (OpenAPI 3.1 specs, JSON Schemas, MCP tool manifests), and enumerates the change classes detected (removed fields, new required inputs, narrowed enums, type mutations). It explicitly distinguishes itself from the sibling compile_polyglot_type_schemas, 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?

Gives an explicit when-to-use condition (auditing contract revisions for backward compatibility before deployment) and names the alternative tool plus the condition that selects it (compiling new TypeScript/Zod/Pydantic schemas from a sample payload). Nothing about routing 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.