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

No annotations are supplied, so the description carries the full burden. It usefully discloses the authorization model and the non-mutating nature of the call, but leaves unresolved whether a comment counts as a write against a reserved row — the schema's _run_id note warns that writes are refused without a run id, and the description does not clarify whether that applies here. Return value and any notification side effects are also unstated.

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 short sentences, front-loaded with the action and scope, with no redundant restatement of the name. Every clause adds information: scope, permission, and the write distinction.

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 7-parameter tool with no annotations and no output schema, the description covers purpose and permission but not the run/claim requirement, the response shape, or ordering of comments. It is enough to attempt a call but not enough to call it confidently on a reserved row.

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 only 57%, so the description would need to compensate, and it largely does not. Beyond echoing the word 'row' (hinting row_id is singular), it says nothing about the datastore selector, the body constraints, or the underscored org/group/project/run identity parameters that the schema documents only in French.

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 ('Add a comment to ONE datastore row') and emphasizes the singular scope. It distinguishes itself from the write path ('It does not change the row: to change a value, write it') but never names the read-side sibling data_row_comments, so an agent choosing between commenting and listing comments must infer the split.

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 a clear use condition plus an exclusion with an explicit alternative ('to change a value, write it'), which routes to data_write. It states the permission precondition ('Anyone who can read the row can comment'), though it does not say when commenting is preferable to other row operations or whether a claimed run is needed.

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