update_project_variable

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

No annotations are provided, so the description carries the full burden. 'Update an existing...' implies mutation and an existence precondition, but it says nothing about required permissions, whether omitted fields are preserved or reset, whether the `key` itself is mutable, or what the response looks like. For a 9-parameter mutation with zero annotation coverage this is a significant gap.

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?

A single efficient sentence with the verb and resource front-loaded, and no wasted clauses. It is appropriately sized, though brevity here partly reflects under-specification rather than tight writing.

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 mutation tool with 9 parameters, no annotations, and no output schema, the description is too thin. It omits permission requirements, partial-update behavior, and the fact that `project_id` and `key` together identify the target, leaving the agent to reconstruct operating conditions from the schema alone.

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 each parameter is already documented in the schema, which sets the baseline at 3. The phrase 'value or configuration' loosely gestures at the value/masked/protected/raw/description/environment_scope fields but adds no syntax, mutual-exclusion, or partial-update semantics beyond 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?

States a specific verb ('Update') and resource ('existing CI/CD project variable') plus the scope of change ('value or configuration'). It distinguishes itself reasonably from siblings like create_project_variable and delete_project_variable, though it does not explicitly name them.

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?

There is no guidance on when to use this tool versus create_project_variable or delete_project_variable, and no note that the variable must already exist or that at least one mutable field should be supplied. The agent must infer all invocation conditions.

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