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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered; the description still adds value by confirming no drawing and no file creation and by explaining what the result contains on success versus failure. It does not discuss limits such as the 100,000 character cap or validation cost, so it falls short of fully rich behavioral context.

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 usage condition and the input cross-reference are front-loaded before the return-value detail, and every sentence carries information. The middle sentence listing failure and success payloads is a long run-on that could be split, which is the only real structural weakness.

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 validator with an output schema, the description covers the trigger, the shared input syntax, the failure shape, the success shape (including the BFS-based unreachable-step detection) and the non-goals. An agent has everything it needs to call this correctly.

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% and the single diagram parameter is documented in detail in the schema itself, so the baseline of 3 applies. The description only adds that the text is the same as make_activity_diagram's input, which is a useful cross-reference but no new syntax or format meaning.

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 ("activity diagram text checked without a drawing") and explicitly separates itself from the sibling by saying it does not draw the diagram or make files, which is what make_activity_diagram does. An agent can pick between the two without opening either 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 an explicit trigger ("Use this when the user wants activity diagram text checked without a drawing") plus two concrete example utterances ("is my flow valid?", "which steps are not reachable?"), and names the not-this case (does not draw or make files), which routes the agent to the sibling. Nothing is left to inference.

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