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

Annotations cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds what annotations cannot: it discloses that up to seven requests are made on the customer's behalf. It also defines all four outcome values and what data is returned for failed revisions (status, content type, first bytes).

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-loads the probe action and revision list, then follows with outcomes and the create_api_test linkage — good ordering with no filler. It is dense to the point of being a single long block, which slightly hurts scanability.

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?

There is no output schema, so the description carries the burden of describing return values, which it does thoroughly via the enumerated outcomes and per-revision failure details. An agent has everything needed to call it and interpret the result.

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 genuine meaning: it explains when mcpCredentialId matters (servers that refuse with 401/403) and ties it to list_api_test_credentials-adjacent workflow. Minor missed opportunity to state that the probe is unconditional across all revisions regardless of params.

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 ('Probe a remote MCP server') and enumerates the exact protocol revisions covered, so an agent knows precisely what is being tested. It is clearly distinguishable from siblings like create_api_test, which it explicitly precedes.

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?

Explicitly says 'Use this before create_api_test to choose mcpProtocolRevision' and explains the three downstream choices (ANY, NEWEST_SUPPORTED, dated revision). It also gives conditional next steps per outcome, e.g. passing a credential or falling back to ANY when AUTH_REQUIRED is returned.

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