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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral context by enumerating supported YAML features (anchors, aliases, multi-document streams, all scalar types), which tells the agent what inputs will succeed. It omits error behavior on malformed YAML, keeping it below a 5.

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?

Four short sentences with zero filler; the core action is front-loaded, followed by sibling differentiation, capability scope, and use cases. Every sentence contributes distinct information.

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?

An output schema exists, so return values need no explanation, and the annotations carry the safety profile. The description covers purpose, scope, and use cases adequately, with only a minor gap in not linking the multi-document support to the `multi` parameter's effect on output shape.

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 100%, so both `input` and `multi` are already documented in the schema, setting the baseline at 3. The description's mention of multi-document stream support loosely corresponds to the `multi` flag but does not explain the flag or how the return shape changes, adding no 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 ("Parse a YAML string and return the equivalent JSON value") and explicitly positions itself against the sibling json_to_yaml as its inverse. An agent can distinguish it from xml_to_json or format_json 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?

Gives concrete usage contexts (config files, CI/CD pipeline definitions, OpenAPI specs authored in YAML) and names the inverse tool, which aids routing. It stops short of explicit when-not guidance or pointing to alternatives such as json_to_yaml for the opposite direction, so it is clear but not exhaustive.

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