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

No annotations are provided, so the description carries the full burden. It discloses that it reports syntax errors with line/column, lint warnings, and document stats, which is helpful. However, it does not explicitly state that the tool is read-only, does not modify input, or what happens on success/failure. For a validation tool, the behavior is reasonably transparent but could be more explicit about side-effects and return format.

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?

The description is two sentences, front-loaded with the main action, and includes specific details (line/column, lint warning types, stats) without any fluff. Every sentence earns its place.

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 tool with one parameter and no output schema, the description provides sufficient context: it lists the types of errors and stats the agent can expect. It does not specify the exact output structure, but 'Reports...' sets clear expectations. The absence of an output schema is mitigated by the detailed description.

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 for the single parameter 'yaml' is 100%, including a description ('The YAML content to validate'). The tool description does not add additional parameter semantics beyond what the schema already provides, so the baseline of 3 is appropriate.

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 clearly states the tool's function: 'Validate and lint a YAML document.' It also specifies what the validation covers (syntax errors, lint warnings, stats), distinguishing it from sibling tools like convert_yaml and visualize_yaml.

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 when to use this tool—when you need to validate and lint YAML—but does not explicitly mention alternatives or say 'use convert_yaml if you need to convert.' The clear focus on validation makes the usage context obvious, though it lacks explicit exclusionary guidance.

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