Jules MCP Server

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

With no annotations provided, the description carries full burden. It mentions the tool sends messages to 'active' sessions, implying a prerequisite, but doesn't disclose behavioral traits like authentication requirements, rate limits, error conditions, or what happens if the session isn't active. The description adds some context about the tool's purpose but lacks operational details.

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 perfectly structured and concise. It begins with a clear purpose statement, provides usage guidelines, then documents parameters and return value in a clean format. Every sentence earns its place with no wasted words, and information is logically organized.

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 tool's moderate complexity (2 parameters, no annotations, but has output schema), the description provides good coverage. It explains purpose, usage context, parameters, and return value. The output schema existence means the description doesn't need to detail return values, and it adequately covers the essentials for this communication tool.

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 provides meaningful semantic context for both parameters. It explains that session_name is a 'resource name' with an example format ('sessions/abc123') and that message is 'the message to send to Jules.' This adds significant value beyond the bare schema, though it doesn't cover validation rules or constraints.

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 specific action ('send a follow-up message') and target resource ('to an active Jules session'), distinguishing it from sibling tools like create_session or get_session. It provides a concrete verb+resource combination that leaves no ambiguity about what this tool does.

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 explicitly states when to use this tool: 'to provide additional context, clarify requirements, or respond to Jules when it's waiting for user feedback.' It provides clear usage context and distinguishes this from other session-related tools by focusing on ongoing interaction rather than session creation or retrieval.

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