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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false. The description adds real context that the project is derived from the ticket (there is no project parameter), but it never warns that a non-idempotent re-call creates a duplicate entry — a meaningful omission 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?

Three tight sentences with the purpose front-loaded and no filler. The trailing 'steps of 15' sentence mildly duplicates the schema's multipleOf constraint rather than adding to it.

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 5-parameter mutation tool with annotations present and no output schema, the description covers the non-obvious derivation rules (project from ticket, service default) and the duration granularity. Missing only the duplicate-entry risk and any hint of the created entry's shape.

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 80%, so the schema already documents ticket_id, service_id, date, and the duration constraints (minimum 15, multipleOf 15). The description mostly restates that coverage — service default and duration steps both appear in the schema — with the only genuinely new detail being that project is inherited from the ticket. Baseline 3 fits.

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 ('Books time for the user on a ticket'), which is clearly distinguishable from update_time_entry or delete_time_entry. It doesn't explicitly contrast against the closest sibling book_stopwatch, so it stops short of a 5.

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?

Usage is only implied — an agent can infer this is for creating a manual time entry, but nothing states when to prefer it over book_stopwatch, start_stopwatch, or update_time_entry, and no prerequisites or exclusions are given.

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