Look up a registry server on the board

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

With no annotations, the description carries the full behavioral burden. It does disclose that the data is a 'latest daily probe', which tells the agent the figures are cached/snapshotted rather than live — a genuinely useful trait. However, it says nothing about what happens for an unknown server, auth requirements, or rate limits.

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?

Two sentences, zero waste: the return contents are front-loaded and the input contract follows. Each clause (probe freshness, field list, accepted formats) earns its place given there is no output schema.

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 one-parameter lookup tool with no output schema and no annotations, the description usefully covers both what comes back and what to pass in. Minor gaps remain around error/not-found behavior and whether the probe requires the server to already be listed in the registry.

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 0% for the single required parameter, so the description must carry it — and it does, specifying the two accepted input forms (registry name in io.github.owner/name format, or the server URL). That is exactly the format guidance the bare 'string' schema omits, though it does not say whether one form is preferred or when one fails.

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 (look up) and resource (a server in the official MCP registry) and enumerates what the probe returns (status, token cost, tool count, latency, history). This clearly distinguishes it from search_servers (discovery) and measure_server (measurement), though it never names those siblings explicitly.

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 scoping phrase 'in the official MCP registry' narrows the domain, but there is no statement of when to prefer this over measure_server, measure_config, or search_servers, and no prerequisite or exclusion guidance. An agent must infer the single-server-identity vs. discovery/measurement split on its own.

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