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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds substantial behavior beyond them: it does not call the servers, does not consume a live-check credit, drops unsafe rows, and consumes the daily quota. It also discloses the return shape and an alias name, none of which appear in structured fields.

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?

Purpose is front-loaded, followed by routing guidance, exclusions, behavioral costs, and return fields. Every sentence carries a distinct fact — usage, non-usage, side effects, output, quota, alias — with no filler.

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 enumerating the returned fields (summary, checked_at, alternatives[] with server, url, verdict, latency_ms, matching_tools). Combined with quota cost, alias, and sibling routing, an agent has everything needed to call and interpret it.

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 (query, limit) are already fully documented with type, range, default, examples, and the no-paging note. The description adds no further parameter syntax or format detail, so the baseline 3 applies.

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 ('Search the Toolweather index for healthy MCP servers') plus the two distinct use cases (capability lookup vs. replacing a broken server). It explicitly distinguishes itself from check_mcp_server_health and watch_server by name, so an agent can route without opening schemas.

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 explicit trigger conditions ('when check_mcp_server_health is unsafe or unknown, or when you lack a capability') and explicit non-use cases pointing to the correct siblings. Nothing about when to pick this tool over alternatives 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.