create_session

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

With no annotations, the description carries the full burden of behavioral disclosure. It mentions the key steps (clone, execute, PR), but omits important traits such as auto_pr defaulting to true, the long-running/asynchronous nature of the session, and potential side effects like modifying the repo or needing authentication. This is a moderate disclosure, not comprehensive.

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 exceptionally concise—two short, direct sentences. It front-loads the purpose ('Create a new Jules coding session') and immediately explains the behavior, with no filler or redundant content.

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 no output schema and no annotations, the description is only partially complete. It explains what the tool does at a high level but does not describe return values, session lifecycle, how to track progress, or how it differs from create_session_from_issue. For a 5-parameter mutation tool, this is a notable gap.

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 covers 100% of parameters with descriptions, so the baseline is 3. The tool description adds no additional parameter meaning beyond restating the auto_pr behavior in prose; it does not clarify formats, relationships, or constraints beyond what the schema already provides.

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 identifies the action ('Create a new Jules coding session') and the resource, with a specific verb and context. It explains the session's workflow (clone repo, execute task, optionally create a PR), which differentiates it from sibling tools like list_sessions and get_session, and from create_session_from_issue, which presumably starts from an issue rather than a direct prompt.

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 implies the primary use case (starting a session to run a coding task on a repo) but does not explicitly state when to use this tool over create_session_from_issue or when to use list_sessions/get_session. No exclusions or alternative recommendations are provided, so guidance is only implied.

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