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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds genuinely new behavior: the token is durable and screen-scoped, and re-submitting the same code/claimKey is idempotent, recovering the original grant rather than minting a new one. It omits error behavior for an invalid or expired code.

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: the primary action leads, the idempotency caveat follows. 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?

With no output schema, the description usefully characterizes the return value (a durable, screen-scoped control token). The main remaining gap is the optional claimKey and failure modes for an invalid pair, but for a two-parameter tool this is largely sufficient.

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 0%, so the description must carry parameter meaning. It does name both inputs and their roles (pairing 'code', 'recovery claimKey'), but it never explains the 43-character claimKey format, the 160-char code limit, or that claimKey is optional and what omitting it implies.

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 names a specific verb and outcome: it exchanges a pairing code plus recovery claimKey for a durable, screen-scoped control token. That is concrete enough to distinguish it from pairing_status and disconnect_canvas, though no sibling is named explicitly.

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?

There is no statement of when to call this versus pairing_status (to check state first) or disconnect_canvas. The idempotency note hints at retry safety but is not framed as usage guidance, so the agent must infer the call timing.

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