Save my man-hours

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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds the crucial nuance that only listed tasks are overwritten while other tasks on that day are kept — i.e. a partial merge, not a full-day replace. It also discloses the closed/fixed period lock, which is a real failure condition an agent must anticipate; what it omits is error/response behavior for locked days or invalid task-project pairings.

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?

Four short sentences, front-loaded with the mutation semantics, then the alternative tool, then ID discovery, then the lock constraint. Every sentence carries actionable information with no restatement of the name or title.

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 two-parameter mutation tool with no output schema, it covers write semantics, sibling routing, ID sourcing, and the locked-period precondition. Remaining gaps are edge-case behavior — what happens when a projectId/taskId pair mismatches, or the exact failure signal on a closed day.

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%: date and minutes are documented in the schema, but projectId and taskId are not. The description compensates by saying these IDs come from list_projects/get_my_projects and list_tasks, and by framing the payload as 'minutes per project task', which clarifies why both IDs are paired per entry.

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 pair (create or update) and resource (your own man-hours for one day), and further scopes the unit as 'minutes per project task.' It also names the sibling delete_manhours for the opposite operation, so an agent can distinguish it from get_manhours without opening a schema.

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?

Explicit routing: removal goes to delete_manhours, ID lookup goes to list_projects/get_my_projects and list_tasks, and days that are closed (締め) or fixed (確定) cannot be changed. That is when-to-use, when-not-to-use, and prerequisites all in one place.

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