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

With no annotations provided, the description carries the full burden of disclosing side effects. It mentions 'fetch' (network call) and 'compare' (read operation) but omits the default side effect of saving to history (save parameter defaults to true). This is a significant transparency gap for a tool that persists state by default.

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 two sentences, front-loaded with the primary action, and wastes no words. Each sentence adds a distinct usage scenario, making it both concise and informative.

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?

The tool has 4 optional parameters and no output schema, yet the description does not explain what the tool returns or how it handles ambiguous cases (e.g., providing both endpoint_id and snapshot_a/b). It covers the core purpose but leaves out return value details and edge-case behavior, making it only minimally complete for a tool with no annotations.

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%, so the baseline is 3. The description adds semantic value by explaining the two parameter modes (endpoint_id vs snapshot_a/snapshot_b), which clarifies how the parameters interact and when each is appropriate. This goes beyond simple property descriptions and earns a 4.

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 clearly states the tool's primary function: 'Fetch a registered endpoint and compare against its last snapshot to detect schema changes' and immediately provides an alternative use case: 'compare two inline JSON objects directly.' This distinguishes it from sibling tools like register_endpoint or detect_breaking_changes by focusing on the comparison action.

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 clear context for when to use each mode: use endpoint_id for registered endpoints, or snapshot_a/snapshot_b for inline comparison. It doesn't explicitly name alternatives like detect_breaking_changes, but the two distinct usage patterns effectively guide the agent. Missing explicit exclusions or 'when not to use' guidance, preventing a 5.

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