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

Beyond the annotations (which only say not read-only, not destructive, not idempotent), the description discloses material behavior: the note is stored for a human to read, is never shown publicly, is rate limited per caller, and the contact field is used only for a reply. Those are exactly the facts an agent needs before submitting user-supplied text to an external team.

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?

Roughly three short sentences with zero filler: what it does, how it behaves, and how to fill the optional fields. The behavioral facts (private, human-read, rate limited) are packed into one clause rather than spread across padding, and the purpose is front-loaded.

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 low-complexity, three-parameter submission tool with an output schema and full schema descriptions, the description covers purpose, behavior, privacy, rate limiting, and per-parameter intent. Nothing an agent needs in order to call it correctly is missing.

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 baseline is 3; the description still adds real meaning by clarifying that contact is optional and used solely to reply, and by stating when page should be populated. It does not restate the 4000-character limit or the plain-words framing of message, but those are already in the schema.

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 opens with a specific verb and resource — 'Send a private note to the cve.now team' — and immediately enumerates the concrete cases it covers (wrong summary, severity, affected version, missing vulnerability or technology, broken feed, feature request). This clearly separates it from the read-oriented siblings (search, get_vulnerability, list_feed, get_leaderboard, check_stack) which cannot write anything.

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?

It gives a concrete list of situations that should trigger the tool, which is stronger than most definitions, and it directs the agent to include the entry id or page when the note concerns a specific record. It stops short of an explicit exclusion (e.g., 'do not use for account or billing issues' or 'use X instead'), so it is clear context rather than full when/when-not guidance.

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