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

Goes well beyond the annotations (readOnlyHint=false, openWorldHint=false), disclosing exactly what is destroyed (the in-progress transfer cannot be resumed) and what survives (already-transferred posts stay in the receiver). It also pre-empts the natural follow-up concern about duplication when starting a fresh import, which is precisely the state-transition context a mutation tool needs.

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 sentences, each earning its place: the first front-loads the effect and the preserved state, the second covers the irreversibility and restart path. No repetition of the tool name or padded phrasing.

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 single-parameter mutation with no output schema, the description covers effect, state after the call, and re-entry semantics. The only gap is the failure path — nothing says what happens when no import is active or what the response looks like — but the rest is sufficient to invoke the tool correctly.

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% and the routeId description already tells the agent where to obtain the value (routes.list), so the schema carries the full parameter burden. The description adds nothing about routeId format or edge cases (e.g. an invalid or already-finished route), leaving this at the baseline.

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+resource: cancelling a route history transfer, and enumerates the exact stages it terminates (counting, waiting for post selection, active transfer). It also distinguishes itself from the pause/resume/start siblings by declaring the cancellation irreversible, so an agent can separate import_cancel from import_pause without reading either 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?

Usage is clearly implied by the irreversibility statement — use this when the transfer should be abandoned rather than merely halted — and by the guidance to start a new import instead. It never names import_pause or import_resume explicitly as the alternative, so an agent must infer the pause-vs-cancel choice from semantics rather than a direct pointer.

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