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

Annotations cover the safety profile (readOnlyHint false, idempotentHint false, destructiveHint false), but the description adds real behavioral context beyond them: mail-to-note conversion, subject-as-title, attachments carried across, and the crucial security caveat that the address is a secret anyone can write to the folder with. That is exactly the extra context the annotations do not provide.

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 purpose, then behavior, then parameters, then an imperative reminder. It is a single dense paragraph but each clause carries information; the parenthetical parameter list is slightly verbose but not wasteful.

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, yet the description explains the return concept ("the returned address") and how it should be handled, and it documents every parameter's effect. For a creation tool with three optional params, this is complete enough to call correctly.

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%, so the schema already documents all three parameters, giving a baseline of 3. The description nonetheless adds semantics beyond the schema, notably that tags are added alongside an automatic 'email' tag and that label becomes the first part of the generated address.

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 ("Create an email capture address") and immediately explains the mechanism (mail becomes a note in a folder). It is easily distinguishable from the sibling email-addresses-list.

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 explains what the tool does and gives an operational instruction ("Tell the user the address once..."), but it never states when to use this versus related creation tools like notes-create or containers-create, nor any prerequisites. Usage is implied rather than guided.

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