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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior beyond that: the required read permission and the specific 404 semantics for foreign, malformed or ephemeral ids. It stops short of describing response contents in detail, relying on the list/create shape instead.

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 short sentences, front-loaded with the purpose and followed by error behavior and sibling routing. The phrase "as the list and the create answer carry it" is slightly awkward but does carry real information about the returned shape.

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, and the description compensates by tying the return value to the list/create representation and documenting the 404 case. For a single-parameter read tool this is nearly complete; only the exact field set of the returned test is left implicit.

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% and the id property already documents that the value comes from GET /targets or the POST /targets answer. The description repeats that source via list_targets and adds only the 404 nuance, so it adds little meaning 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?

States a specific verb and resource ("Get a saved test") and immediately scopes the result to exactly one record, which separates it from list_targets. It also names get_target_vendors as a different view, so the agent can distinguish it from siblings 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?

Explicitly routes the agent: find the id with list_targets, and use get_target_vendors for vendor/monitoring state. It also gives the failure condition (foreign, malformed or ephemeral id yields 404), which tells the agent when this call will not work.

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