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

Goes well beyond the readOnly/idempotent annotations by disclosing that it does not contact remotes, never spends a live-check credit, that each name consumes one Toolweather quota call, that an over-quota batch becomes a single $0.01 x402 charge, that unknown names yield verdict 'unknown', and what the response contains. This is exactly the billing and side-effect context an agent needs before batching.

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 purpose, then constraints, then cost model, then return shape — four tight sentences with no filler. Every sentence carries information the agent would otherwise have to guess.

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?

With no output schema, the description compensates by naming the return fields (summary, checked_at, results[] verdict fields) and the unknown-name behavior. Combined with the billing and no-network disclosure, an agent has everything needed to call this 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 coverage is 100%, so the baseline is 3, but the description adds quota-cost meaning beyond the schema: each entry counts as one daily call, and unknown names return verdict unknown. It does not add format examples for the URL form, which keeps it short of a 5.

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 and resource ('Read stored health verdicts'), quantifies scope ('up to 25 MCP servers'), and explicitly distinguishes itself from check_mcp_server_health and find_alternative_mcp_servers. An agent can tell exactly what this returns 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?

Gives an explicit when ('use at startup to vet that list') and two explicit when-nots with the correct alternative named for each (live handshake/auth detail → check_mcp_server_health; capability discovery → find_alternative_mcp_servers). 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.