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

With no annotations provided, the description carries the full behavioral burden and discloses important traits: it is a bounded analysis rather than a complete compatibility proof, does not execute endpoints, seeds baseline history on first call, requires payment or trial credentials, and warns against automatic payment. These details go well beyond the schema and are materially useful for safe invocation.

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 a single sprawling block that buries core invocation guidance under extensive payment, trial, protocol, and recovery details. While the first sentence is front-loaded, the overall length and branching billing instructions make it hard to scan for the essential diff-tool 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?

For a complex paid diff tool with no output schema, the description supplies the required context: prerequisites, return evidence categories, limitations, first-call baseline behavior, payment/trial requirements, and recovery guidance. An agent has enough information to decide whether and how to attempt the call, even though the text is verbose.

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%, and the schema already documents watch_id, compare_to, and previous_hash including patterns, defaults, and enum values. The description repeats some of that meaning and adds little parameter-specific information beyond what the schema provides, so the baseline of 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?

The opening sentence names a specific action and resource: reviewing supported directional contract changes before an API integration update. It is clear what the tool does, but it does not explicitly distinguish itself from sibling tools such as fresh402_smart_diff or fresh402_contract_watch.

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 gives explicit timing guidance ('Use before an API integration update'), states the required watch_id prerequisite, and names an alternative ('A local tool such as oasdiff may be preferable for larger/unsupported contracts'). It also lists unsupported cases such as YAML, external-reference fetching, and endpoint execution.

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