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

Annotations already cover readOnly/idempotent/non-destructive, yet the description adds real domain semantics: the four possible health states, what RATE_LIMITED actually means (HTTP 429, fix on the customer side), and that currentRevision is null until the first run for MCP tests. It does not cover error behavior for an unknown id, which is the main remaining gap.

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 action and scope, then the semantic carve-outs. Every sentence carries information, though the RATE_LIMITED explanation is longer and more awkwardly wrapped than needed for a single-record fetch.

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 does the work of explaining what comes back: full configuration, health state, and consecutive-failure count. It stops short of describing the shape of 'full configuration', but an agent has enough to call 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?

One parameter at 100% schema description coverage, so the schema already explains apiTestId. The description adds no id format, provenance, or example beyond what the schema states — 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 ('Fetch'), resource ('API test'), and scope ('a single ... by id'), plus enumerates the returned fields. This clearly separates it from list_api_tests (plural listing) and from get_api_test_runs/get_api_test_destinations (different sub-resources).

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?

Usage is implied by the 'by id' framing — an agent knows it needs an id, presumably from list_api_tests — but there is no explicit when-to-use, no named alternative, and no stated preconditions. Adequate but leaves routing to inference.

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