time_create_timer

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

With no annotations, the description carries the full burden and does well: it discloses that user_id cannot be set, that an existing running/paused timer is resumed and returned rather than duplicated (idempotent behavior), and that billable defaults to the account setting. It does not mention permission requirements or return payload details.

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, front-loaded with the primary action, then the dedupe behavior, then the default and the alternative. No filler or repetition of the schema.

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?

No output schema exists, and the description covers the key non-obvious return behavior (resumes and returns the existing timer). What is missing is minor: any note on autoupdating notes/comment linkage or error cases, but nothing an agent needs to invoke correctly is absent.

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 100%, so the baseline is 3, but the description adds real meaning beyond the schema: it explains the billable default behavior and the implicit constraint that user_id/ticket ownership is derived from the token rather than settable.

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 states a specific verb and resource ("Start a live timer on a ticket") plus the scope constraint (for the API token's technician). It explicitly names the sibling tickets_add_timer as the wrong tool for past work, so an agent can distinguish it 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?

It gives a clear when-to-use rule and an explicit exclusion routing the agent to tickets_add_timer for logging past work. However, it never mentions the very similar sibling time_start_timer, leaving one obvious alternative unaddressed.

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