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

The description adds significant behavioral context beyond annotations, such as sending a confirmation link, proof of ownership requirement, and lack of silent merging. No contradiction with annotations (readOnlyHint=false, destructiveHint=false) as the description aligns with a non-destructive mutation.

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?

The description is concise (3 sentences) with front-loaded main action and no redundant information. Each sentence provides distinct value: action, verification, preconditions, and conflict resolution.

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?

Given the tool's low complexity (1 param, no output schema, clear annotations), the description fully covers the use case: preconditions, user interaction steps, verification, and edge cases. No gaps remain.

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% for the single parameter 'email'. The description adds meaning by specifying that the email must be real, user-owned, and for accounts without existing email, which is useful context beyond the schema's generic description.

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 uses specific verbs ('attach', 'sends a confirmation link') and clearly identifies the resource ('real email address to the signed-in user's phone-keyed TuLugar account'). It distinguishes itself from siblings by focusing on email linking for accounts created via WhatsApp, which is unique among the sibling tools.

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 explicitly states when to use (accounts without a real email) and what to do before calling (ask for email, confirm it back). It also describes behavior when the email belongs to another account, but does not explicitly mention alternatives or when not to use beyond the precondition.

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