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

Adds substantial behavior beyond the annotations: the prior signup link is invalidated, the email is re-sent to contact_email, sending is throttled to at most once per day per address, and the 'emailed' field reports whether delivery happened. This is exactly the kind of operational detail an agent needs before invoking a destructive, non-idempotent tool.

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-loads the 'Sandbox only' constraint and packs the trigger, side effects, and rate limit into compact prose with no filler. The grammar is slightly run-on ('emailed says whether it went'), but nothing is wasted.

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?

There is no output schema, and the description compensates by explaining the 'emailed' indicator and the email side effect. Combined with annotations covering destructiveness and idempotency, an agent has enough to call it correctly; only the full response shape is left implicit.

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?

With zero parameters the baseline is 4, and the description adds value by naming the output field 'emailed' and explaining what it means. No further parameter detail is needed for a no-arg tool.

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: "Issues a new claim link for your human." It also clarifies the lifecycle (the signup link stops working), which distinguishes it from a generic link creator. It does not, however, differentiate itself from the sibling create_connect_link, so an agent may still hesitate between the two.

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 an explicit trigger: "Call it when you lost the signup response," which is clear context for use. It lacks an explicit when-not or a pointer to create_connect_link as the alternative for a different link type, so it stops short of full routing guidance.

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