update_service_env

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

Without annotations, the description carries the burden of behavioral disclosure. It mentions one key behavior: 'Setting is_build_time=true has no functional effect on services.' However, it does not explain other behaviors such as idempotency, error handling for missing variables, or whether updating triggers a redeployment.

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?

The description is concise at two sentences, front-loading the core purpose. The note about is_build_time is relevant but slightly misplaced. Overall, every sentence contributes without redundancy.

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?

Given the absence of an output schema, the description should explain the result of updating (e.g., returns updated variable, triggers redeployment). It does not touch on side effects or preconditions (e.g., variable must exist). It is adequate but incomplete for a full understanding.

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?

The input schema has 100% coverage with descriptions for all 6 parameters. The description adds minimal new information beyond the schema—only noting that is_build_time has no effect, which is already in the schema's description. It does not clarify relationships between parameters like is_literal and is_preview.

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 clearly states the action: 'Update an existing environment variable for a service.' It specifies the verb 'Update' and resource 'existing environment variable for a service,' which differentiates it from create or delete operations and sibling tools like bulk_update_service_envs or update_application_env.

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?

The description provides no guidance on when to use this tool versus alternatives like bulk_update_service_envs for multiple updates or create_service_env for new variables. It lacks explicit conditions or exclusions, leaving the agent to infer the appropriate context.

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