Set an environment variable

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

Goes well beyond the annotations by disclosing that the value is persisted to the environment's file and shared through Git, and that a missing environment is created as a side effect. It does not say what happens when the key already exists (overwrite vs error), which matters given idempotentHint=false.

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: capability, persistence/Git implication, then the security boundary. Front-loaded with the action and scoping constraint, with no 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?

With no output schema and full schema coverage, the description supplies the missing behavioral context: Git persistence, non-secret constraint, and environment auto-creation. Only the overwrite behavior for an existing key is left unexplained.

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 description coverage is 100%, so all five parameters are already documented, including the environment default and workspace disambiguation. The description adds no additional parameter meaning, 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 (set a non-secret variable in an environment) and immediately scopes it away from secrets and protected environments. An agent can distinguish this from list_environments or save_request without reading the 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?

Explicitly names the negative case: 'never use it for a secret' and directs secret/protected changes to Kurlo. It also documents the side effect of creating a missing environment. What's missing is a positive routing rule toward a sibling tool (e.g., when to prefer list_environments first), but the exclusions are strong.

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