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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered without help from the description. The description adds useful behavioral context about the payload ('every span, with timings and nesting') and pins the underlying API call. It says nothing about trace size, truncation, pagination, or auth requirements, so it is a moderate-but-not-rich addition given the annotation coverage.

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 action and scope before the use-case framing. The trailing 'Trigger.dev: GET /api/v1/runs/{runId}/trace.' is largely provenance filler that duplicates the operation already stated, keeping it just short of a perfect score.

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 simple one-parameter read tool with readOnlyHint set and no output schema, the description covers purpose, the debugging use case, and the shape of what is returned (spans, timings, nesting). It lacks any note on response volume or handling of very large traces, which is the only real gap for an agent calling it blind.

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?

There is a single parameter (run_id) with 100% schema description coverage ('The run's id.'). Per the rubric this is the baseline 3: the schema fully documents the parameter and the description adds no format, source, or constraint detail beyond it.

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 and resource ('Fetch the full execution trace of a run') and scopes it precisely with 'every span, with timings and nesting.' This implicitly separates it from the sibling trigger_get_run_span (single span) and trigger_get_run (run summary/status), but neither sibling is named explicitly, so the differentiation is left to inference.

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 framing 'The tool for "where did this run spend its time, and where did it break?"' gives a clear, concrete use case that an agent can match to a debugging/performance task. It stops short of stating when NOT to use it or naming alternatives (e.g., use trigger_get_run_span for one span), so it doesn't reach the explicit when/when-not bar.

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