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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), and the description adds useful behavioral context: it returns an independent cached probe with 7-day reachability, recent tool-list changes, and a likely cause of failure, implying results are observed not authored. It doesn't disclose freshness/latency or rate limits beyond 'latest', so it stops short of full disclosure.

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?

Three sentences, front-loaded with the trigger condition and the diagnostic framing; the colloquial opener 'Is it me or is it them?' earns its place by telegraphing the diagnosis purpose, though it is slightly less information-dense than the rest.

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 usefully enumerates what comes back (status, OAuth flow, 7-day reachability, tool-list changes, likely cause), which is enough to interpret results. Minor gaps remain around how the two identified failure modes and 'reason' values interact, but nothing essential is missing for calling it 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% with all three parameters documented in-schema, so the baseline is 3. The description adds no per-parameter detail (e.g., URL-vs-name precedence when both are supplied, or how 'reason' affects the probe), so it does not go beyond the schema.

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 names a specific verb (probe/check) and resource (a remote MCP server) and spells out the exact result categories it produces (up / auth required / down). It is functionally distinct from find_servers (discovery) and report_outcome (reporting), so an agent can tell it apart without opening a 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?

It gives explicit, concrete triggers: on connection error, 401/403, timeout, or missing tool, and proactively before adding a server. The failure taxonomy maps directly to the situations an agent will encounter, leaving little to inference.

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