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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds value by enumerating what the response contains (status, output, error, attempts) even though no output schema exists, but it says nothing about failure modes, missing-run behavior, or size/pagination of results.

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 short sentences, front-loaded with the payload summary. The API endpoint sentence is mildly redundant but does confirm the resource path and the runId placement; nothing else is wasted.

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 single-parameter read-only fetch with no output schema, the description covers what an agent needs: the resource, the required identifier, and what comes back. Only the sibling-routing question (which of the several run-related getters to call) is left open.

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?

With one parameter at 100% schema description coverage, the schema already documents run_id and its run_... format. The description contributes only the API path hint and adds no semantics beyond that, so the 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 and resource ("Fetch a single run's outcome") and enumerates the returned fields — status, output, error, attempts — which separates it from metadata/span/trace siblings. It stops short of naming those siblings explicitly, so the differentiation is implied rather than stated.

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 description implies the usage context (you have a run_id and need that run's result), but gives no when/when-not guidance against the many closely-named siblings such as trigger_get_run_metadata, trigger_get_run_span, trigger_get_run_trace, or trigger_list_runs. An agent must infer the routing itself.

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