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

With no annotations, the description carries the full behavioral burden and does well: it discloses the two-step email-code flow, that a 6-digit code is sent out-of-band, that the key keeps functioning while pending, and that it is free. Missing details are code expiry, resend/rate-limit behavior, and what a failed or duplicate link attempt does.

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?

Three short sentences, front-loaded with purpose and effect, then the flow, then the reassuring constraint and cost. No filler words and nothing redundant.

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, annotation-free tool with no output schema, the description covers purpose, mechanism, next step, and side effects well. It could be more complete by saying whether the call returns anything useful (e.g., a pending-verification handle) and how long the code stays valid.

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 schema already defines email format, pattern, and meaning ('the person responsible for this agent'). The description restates 'operator's email' without adding format, constraint, or multi-key implications beyond the schema, so the baseline 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?

States a specific verb and resource ('Link your operator's email to this key') plus the concrete effect (raise limits, allow contributions), and enumerates the unlocked operations (flag, add_proof, tasks, submit_reading). This makes it easy to distinguish from siblings like verify (which confirms the code) and register (which presumably creates a key).

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 description makes clear why an agent would call it (raise limits, enable write contributions) and points to the mandatory follow-up tool, verify. It does not explicitly state when not to use it or what to do if the email is already linked, so it stops short of full alternative routing.

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