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

With no annotations provided, the description carries the full behavioral burden. It says 'update' (a mutation) but does not disclose whether the update is partial or full replacement, what happens if item_id doesn't exist, whether permissions are required, or what the response looks like. For a mutation tool with zero annotation coverage this is a significant gap.

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?

Two short sentences, front-loaded with the action and followed by the required input. Efficient, though the second sentence is largely redundant with the schema and could have carried behavioral detail instead.

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?

Parameters are fully covered by the schema and the purpose is clear, but for an unannotated mutation tool with no output schema the description is thin on behavior: no auth/permission context, no error semantics, and no confirmation of partial-update behavior. Minimum viable rather than complete.

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 the schema already documents item_id, title, and done. The description only restates 'Provide item_id and fields to update,' adding no syntax, format, or constraint detail beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('update') and resource ('checklist item'), plus the exact fields affected (title, done status). This distinguishes it from add_checklist_item, delete_checklist_item, and list_checklist without naming them, so it is clear but short of explicit sibling differentiation.

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 opening 'Use this to update...' implies when the tool applies, but there is no explicit when-not guidance and no named alternative (e.g., delete_checklist_item for removal, add_checklist_item for creation). Usage is inferable from the purpose rather than stated.

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