share_diagram

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

Beyond the annotations (readOnly/idempotent/non-destructive/closed-world), it discloses that the source is compressed into the URL fragment, nothing is uploaded, the link works for anyone, the return is plain text, and the failure mode reports both sizes. That is substantial behavioral context the annotations alone do not convey.

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 tightly packed sentences with no filler; the purpose, behavior, failure mode, and prerequisite are all front-loaded in a logical order.

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?

With no output schema, the description still covers the return value ('returns the URL as text'), the error behavior, and the validation prerequisite, so an agent has everything needed to call it 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?

Only one parameter (dgmo), and schema description coverage is 100%, so the schema already documents it. The description refers to 'the source'/'compressed source' but adds no format, encoding, or size-limit specifics beyond what the schema and error text imply — baseline 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?

States a specific verb and resource: 'Generate a shareable diagrammo.app URL for a DGMO diagram.' This is clearly distinct from siblings like validate_diagram, render_diagram, and open_in_app, and the agent can identify the operation without opening the 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?

Explicitly names alternatives and the conditions selecting them: on size-limit errors, 'split or simplify the diagram, or use open_in_app / render_diagram instead,' and it directs the agent to 'call validate_diagram first' since the source is not validated here. This is genuine when/when-not routing.

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