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

Annotations already mark this as a non-read-only mutation. The description adds useful behavioral context: the item is added to a shared checklist, so it is visible to all participants, and the action is taken as the participant, implying identity attribution via participant_id and token. It does not cover duplicate handling or failure modes, but these are minor gaps for this operation.

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?

A single sentence that front-loads the action and resource, followed by a concrete example. Every word earns its place, and the example is useful without bloating the description.

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 4-parameter mutation with full schema coverage, the description plus schema provide enough to know what the tool does and how to invoke it. It lacks an explicit return-value description and clear alternative-tool routing, but those gaps are minor given the straightforward operation and accessible sibling list.

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 is 100%, with descriptions for all four parameters. The description adds only an illustrative example for the text parameter and does not contribute additional semantics for plan, participant_id, or participant_token, so the baseline 3 applies.

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 ('Add') and resource ('plan's shared checklist') with a concrete example ('Bring the grill'). The action is clearly distinct from siblings like check_item (marking an item) and get_checklist (reading the checklist).

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?

Provides no explicit when-to-use guidance or alternatives. The phrase 'Acts as the participant' hints at contextual use but does not say when to prefer this tool over check_item or get_checklist, nor does it mention any exclusions or prerequisites.

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