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

Annotations already declare readOnly, idempotent, and non-destructive. The description reinforces this by explicitly stating 'does not mutate artifacts or submit courses.' It also discloses the two input modes (artifact or inline JSON). This adds behavioral context beyond the annotations without contradicting them.

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 sentences, no filler. The purpose is front-loaded, the non-mutation behavior is explicit, and every phrase adds information. It is an ideal size and structure.

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?

The description captures the tool's purpose and non-mutating behavior, and the output schema covers return values. But it leaves a critical ambiguity about how to choose between the two parameters and whether at least one is required. For a tool with zero required parameters, this is a meaningful gap that could lead to incorrect invocation.

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 description coverage is 50%: only crsprof_artifact_id has a schema description, while crsprof has none. The description partially compensates by labeling crsprof as 'inline CRSProf JSON' and clarifying the two input modes. However, it does not explain whether one of the two parameters is required, whether they are mutually exclusive, or what happens when both or neither is provided. With required empty, an agent could misinvoke the tool without guidance.

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 (validate), a specific resource type (CRSProf artifact or inline JSON), and the timing (before race planning or catalog submission). The explicit 'does not mutate artifacts or submit courses' distinguishes it from sibling submit_course and similar mutation tools. The resource type also differentiates it from validate_runner_profile.

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?

Tells the agent when to use it: before race planning or catalog submission. Implicitly tells the agent not to use it for mutation or submission by stating it doesn't do those. However, it does not explicitly name alternative tools or describe when to use other validation tools like validate_runner_profile, so it's clear context but no explicit exclusions of alternatives.

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