Invalidate a timer estimate after known external changes so stale timing data is not reused; does not inspect or mutate the page.
Invalidate a timer estimate after known external changes; does not inspect or mutate a page.
| Name | Required | Description | Default |
|---|---|---|---|
| reason | No | ||
| timer_id | Yes |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the safety profile is covered. The description adds a useful scope clarification ('does not inspect or mutate a page'), but it does not say what is lost when an estimate is invalidated, whether the timer must be re-prepared afterward, or whether the operation is reversible.
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?
A single semi-colon-joined sentence with zero filler, front-loading the action and then the constraint. It is arguably too compressed for a destructive tool, but nothing is wasted.
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?
With only two parameters and no output schema, the tool is simple, but a destructive operation should at minimum explain the effect on subsequent timer operations and what 'reason' is used for. The description covers scope but not consequences, leaving a real gap for a mutating tool.
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 and it does not: the optional 'reason' parameter (1-512 chars) is never mentioned, nor is how 'timer_id' should be sourced. The only parameter-level hint is implicit in the word 'invalidate'.
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 target ('Invalidate a timer estimate') plus a qualifying condition ('after known external changes'), which separates it cleanly from siblings like timer_attach, timer_prepare, and timer_calibrate. It stops short of defining what an 'estimate' is or how invalidation differs from timer_detach, but an agent can still tell what the tool does.
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 phrase 'after known external changes' implies a trigger condition, and 'does not inspect or mutate a page' sets a boundary. However, no sibling is named as an alternative (e.g., timer_calibrate vs. timer_detach vs. this), so the agent must infer the routing decision from the sibling list alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.