jules_start

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states that plan approval defaults to required, which is already visible in the schema default; it does not disclose side effects such as whether a branch is checked out, whether a background process starts, or what permissions are needed.

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 extremely compact and front-loaded, with the core action stated immediately. The second sentence adds a useful behavioral note, though it is somewhat redundant with the schema. It earns a high score for efficiency, though it sacrifices completeness.

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 tool with six parameters, one required, and no annotations, the description is too sparse to support correct invocation. An agent cannot determine what to put in 'prompt', how 'source' or 'branch' should be used, or what side effects starting a session will have. The output schema helps with return values but does not compensate for the missing input guidance.

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?

With 0% schema description coverage, the description needed to explain the six parameters, especially the required 'prompt'. It only mentions the plan approval default, which duplicates the schema's default value. The meaning of 'branch', 'source', 'title', and 'auto_create_pr' remains completely unexplained.

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 states a specific verb and resource: 'Start a Jules coding session.' This clearly distinguishes the tool from all siblings, which are list/status/send/approve/result operations rather than session creation. The additional note about plan approval does not confuse the core purpose.

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 explicit guidance on when to use this tool versus its siblings, nor any exclusions or prerequisites. The only implied usage is 'when you need to start a session,' but no alternatives are mentioned, and there is no discussion of when not to use it.

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