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

Beyond the annotations (which show this is not read-only, not destructive), the description discloses important behavioral traits: each item is 're-checked for conflicts before writing', a slot taken meanwhile is 'reported as an error with a prompt to re-run schedule'. This adds genuine value beyond the annotations by explaining the write-time validation behavior and error handling.

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 sentences, front-loaded with the core action, then parameter mechanics, then conflict-check behavior. Every sentence adds value — no filler, no repetition of what annotations already say. Well structured from purpose to mechanics to edge-case handling.

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 no output schema and moderate annotation coverage, the description explains the input mechanics, the write-time validation behavior, and the error handling scenario. It also covers the meaning of token and choice. It could add what exactly appears in `results`, but overall it's fairly complete for the tool's complexity.

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 50% — the item-level properties are documented, but `render` is the undocumented half. The description explains the token and choice semantics well (token is commitToken, choice is 0-based index, defaults to first/best). However, the `render` parameter's purpose is only in the schema and not reinforced in the description, and the description doesn't fully clarify that the conflict check behavior is what distinguishes this from just writing events.

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 verb 'Confirm' with the specific resource ('proposed times from schedule') and explains the mechanics (pass items with token and choice). It distinguishes itself from the sibling 'schedule' tool by explicitly referencing what schedule proposed and how confirmation works.

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 explains the when-to-use context implicitly by referencing that these are times 'schedule proposed' and how choosing among options works. It doesn't explicitly name alternatives or state when NOT to use it, but the sibling context (schedule, undo) makes the usage scenario reasonably clear.

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