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

Annotations already flag this as a non-read-only, open-world, non-destructive call; the description goes further by disclosing the return contract (monitor id plus a secret shown only once), the signing scheme (HMAC-SHA256 in header MINIMALCULT-Signature), and a quota (3 monitors per address free). That is real context an agent cannot get from the annotations.

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?

Three tight sentences: what it does, what it returns, then the quota. The action and event scope are front-loaded and no sentence is filler.

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 two-parameter subscription tool with no output schema, the description covers the action, trigger events, return values, signing, and quota. Minor gaps remain around verification setup and how to later remove a monitor, but nothing essential to making the call 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 both parameters already document their formats (public https URL, rec_/mcp:/npm:/pypi: identifiers). The description adds only indirect meaning via "webhook" and the free-tier limit; it does not explain payload delivery or retry behavior, so the baseline 3 applies.

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 ("Subscribe a webhook to changes of a record") and enumerates the triggering events (new version, tool description changed, removed). No sibling tool (check, record_get, record_search, record_versions) creates subscriptions, so an agent can select this unambiguously.

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?

Usage is implied by the event list and the required url/record pair, but there is no explicit statement of when to prefer this over polling with record_versions or check. No exclusions or prerequisites (e.g. auth requirements) are given.

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