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

Annotations already declare it is a non-read-only, non-destructive mutation. The description adds substantive behavioral context beyond that: the precise state machine transition (submitted -> approved) and the downstream consequence (operator can activate and accept jobs). It omits reversibility, permissions, and failure modes, but the transition semantics are genuinely informative.

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 tight sentences, front-loaded with the action and followed by the state transition and consequence. No filler or redundancy.

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 one-parameter mutation with no output schema and annotations covering the safety profile, the description supplies the key missing context: what state the resource must be in and what approval unlocks. It could optionally note the read counterpart (get_registration) or whether the action is reversible, but nothing essential for calling it 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 description coverage is 100% and the single registrationId parameter is already documented with a format example ('reg-1234567890'). The description adds no further meaning about the identifier, so the baseline of 3 applies.

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?

Names a specific verb (approve) and resource (submitted machine registration) and describes the exact state transition from 'submitted' to 'approved'. It also distinguishes itself from the nearby siblings activate_registration and reject_registration by framing approval as the precondition that enables activation.

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?

Clear context for when this applies: the registration must be in 'submitted' state, and the outcome enables the operator to activate. It does not state explicit exclusions (e.g. what to do instead when rejecting or when the registration is already approved), so it stops short of full when/when-not guidance.

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