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

With no annotations provided, the description carries full responsibility for revealing behavioral traits. It only states that no auth is required, but omits any information about side effects, idempotency, error behavior, or what happens when the entity is invoked. This is insufficient for a tool that likely triggers an action.

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 a single concise sentence that front-loads the primary purpose and includes the key note about auth. Every word earns its place, with no unnecessary filler or repetition.

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 tool with only two simple string parameters and no output schema, the description is minimally adequate. However, it does not mention what the response looks like, and given the sibling subfeed_chat, it could benefit from clarifying when to use invoke rather than a chat-based interaction.

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?

The input schema already provides descriptions for both parameters ('Public entity ID' and 'Message to send'), covering 100% of the schema. The description adds no additional semantic meaning beyond what is in the schema, so the baseline score 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 action ('Invoke') and the resource ('public entity'), which is specific enough to distinguish it from sibling tools like list/get/create. The addition of 'No auth required' provides a useful qualifier, though the exact meaning of 'invoke' is left somewhat ambiguous.

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 provides no explicit guidance on when to use this tool versus alternatives, such as subfeed_chat. The only contextual hint is 'public entity' and the note that no auth is required, but there is no mention of exclusions or scenarios where another tool would be more appropriate.

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