Stop or discard the timer

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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description discloses atomicity, goal crediting, the 1-minute floor and 12-hour cap with a 'capped' response marker, and that discard writes nothing and loses elapsed time. This is rich behavioral detail that the annotations do not provide.

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?

The description is front-loaded with 'WRITES.' and the main action, then proceeds to edge cases in a logical order. While fairly dense, every sentence contributes essential behavioral or usage detail; there is no filler. It could be slightly tightened but remains efficient.

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 6-parameter tool with no output schema, the description covers the core behavior, edge cases, and usage guardrails. It does not mention what happens if no timer is running, which is a minor gap, but the critical operating details (floor, cap, discard semantics) are fully disclosed.

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 baseline is 3. The description adds significant meaning by stating that 'Attribution fields sent here override whatever the timer was started with,' clarifying the role of goalId, taskId, taskName, and scheduleBlockId. It also explains the discard parameter's effect beyond its schema description.

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 the exact action: 'Stops the running timer and converts it into a time entry, or discards it.' It clearly identifies the resource (timer) and the two possible outcomes, and it distinguishes itself from sibling start_timer by being its inverse.

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 gives clear context: use when a timer is running. It explicitly scopes the discard option with 'Only use it when the user says the timer was started by mistake.' It does not name alternatives like goalslot_log_time for manual entry, but the trigger condition is clear enough.

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