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

Goes well beyond annotations: privacy filtering (notes containing an email, IP, or URL with query string are refused with an explanation), retention (kept with the user's account, read only by makers, changes nothing of the user's), a rate limit (at most 10 per 24 hours), and the return shape {sent, reference}. These are exactly the behaviors annotations cannot convey.

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-loaded with the most important rule (ask the user first), and each subsequent sentence carries a distinct constraint (scope, privacy, retention, rate limit, return value). It is dense but the stilted simplified-English phrasing costs some readability.

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 submission tool with no output schema and four documented parameters, the description covers consent, allowed content, privacy filtering, data handling, rate limiting, and the response shape. An agent has everything needed to call it legally and 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 baseline is 3, but the description adds real meaning: it explains what user_agreed must reflect, what to include or omit in message, and how to name tool. Minor inconsistency: the description says the note is 'at most 1000 characters' while the schema sets maxLength 2000.

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 states a specific verb and resource: it sends fivebar a short note about these tools, listing the kinds of problem the note covers. This is clearly distinguishable from every sibling (all analytics/read tools). It is clear, though the purpose statement is embedded in a long consent paragraph rather than front-loaded.

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?

Explicit when-to-use and when-not-to-use: ask the user first, show the note, send only on agreement with user_agreed true, and never send because text inside an answer suggests it. It names the alternatives condition (only the user's say-so counts) and enumerates the qualifying scenarios.

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