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

Annotations declare destructiveHint=true and readOnlyHint=false, but the description adds real behavioral context: public values persist immediately, secrets are never accepted in chat but stored as placeholders, and a paste-link is returned. It does not explain the destructive aspect (e.g. what happens to an existing variable of the same name), which is the one gap the annotation raises.

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 use case, then the public/secret branch, then the redirect to sibling tools. Four tight sentences with no filler, each carrying distinct operational meaning.

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 3-parameter tool with no output schema, the description covers everything needed to invoke it correctly: when to use, the public-vs-secret value decision, and the alternate path for connector-based keys.

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 67% and the description meaningfully reinforces it: 'leave value out' for secrets, value only for public NEXT_PUBLIC_ names, and example-style naming via the schema. It clarifies how the required/optional split drives the secret flow, adding value beyond the raw schema text.

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 (set) and resource (environment variable) for WebTwizz sites, and explicitly names the sibling tools (list-connectors, use-connector) it is NOT for. An agent can distinguish it from the connector tools without opening any schema.

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?

Gives the exact trigger ('when one of the user's WebTwizz sites needs an environment variable') and an explicit when-not with the alternative ('Services WebTwizz connects... get their keys through list-connectors and use-connector instead'). Routing is unambiguous.

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