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

With no annotations, the description carries the behavioral burden well: it discloses the owner-only restriction, the state transition back to pending approval, and that the reason is recorded in the audit trail. It does not say whether reopening affects already-exported payroll or whether the action is reversible, which leaves a real gap for a mutation tool.

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 tight sentences with the permission constraint and state outcome front-loaded; every clause earns its place.

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 with no annotations, the description covers permission, effect and audit consequences, and an output schema exists to explain returns. Only the downstream impact (payroll, invoicing, prior exports) is left unstated.

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 0%, so the description must compensate: 'the reason is audited' adds meaningful semantics for the reason field, but time_entry_id is never explained beyond the schema's uuid format. Half the parameters remain semantically opaque.

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 ('reopen approved time') and names the resulting state ('goes back to waiting for approval'). This clearly distinguishes it from siblings like timesheets_void, timesheets_decide and timesheets_update without opening their schemas.

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?

'Use this when approved time was wrong' gives a clear trigger condition, and 'Owner only' sets the permission prerequisite. It stops short of naming the alternative actions (e.g. void vs. update) or stating when not to reopen, so it is not a full 5.

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