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

Annotations already declare destructive, idempotent, and non-read-only, so the safety profile is covered. The description adds genuinely non-derivable context: it mutates synthetic state, consumes no target invocation, and is attributed to the operator rather than the target, plus the retry/reconcile guidance. Return format is left unstated but no output schema exists to cover it.

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?

Front-loaded with the core action, then prerequisites, behavior, and caveats in five dense sentences. Every sentence carries information; the wording is terse but not padded.

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 10-parameter destructive mutation with no output schema and 10% schema coverage, the description covers behavior and workflow well but leaves parameter semantics and the expected acknowledgement/return largely unexplained. It is adequate but has clear gaps for a tool of this complexity.

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 only 10% (just operationKey), yet the description compensates only partially: 'alias, instance, epoch and controlOperations' loosely maps to service/instanceId/epoch, and 'Save exact input/key' gestures at operationKey. The remaining seven required parameters (projectId, environmentId, runId, reason, operationId, arguments, operationKey semantics) are undocumented in both places.

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 (Apply) and resource (one explicit permitted control operation to an active run's Tool), which is more precise than most siblings. However, it does not explicitly distinguish itself from the similar-looking siblings firedrill_service_control or firedrill_service_invoke, leaving the agent to infer the boundary.

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?

Gives a clear prerequisite workflow ('Read run_services first for current alias, instance, epoch and controlOperations') and a when-not condition ('Arbitrary reset/clock/fault operations are not implied'). It also warns against retrying as a new intervention. It stops short of naming a specific alternative tool to prefer.

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