Open Companion

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states one behavioral aspect ('does not send work to Claude') and the adjective 'persistent.' It fails to disclose side effects like creating background processes or state persistence details, which are important for an open/create operation.

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 two short sentences. The first states the core purpose, the second clarifies a critical behavioral distinction. No filler or redundancy; every sentence earns its place.

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?

The tool has 15 parameters, no output schema, and no annotations, so the description must be richer to be complete. It does not explain what the result of a successful call looks like, when to use this over companion_start, or any prerequisites. For a complex stateful op, two sentences are insufficient.

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 coverage is 100% and the tool description adds no direct parameter info, but it does provide a helpful semantic clarification ('does not send work to Claude') that indirectly informs parameter intent (e.g., maxTurns, maxBudgetUsd are for later sends). Baseline of 3 is appropriate when the schema fully documents parameters.

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 uses a specific verb-resource combination ('Create or restore the persistent Claude Code companion') and adds a scope ('for a project cwd'). It also clarifies that it does not send work, distinguishing it from companion_send, but does not explicitly differentiate from companion_start or companion_tui_open.

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 use when you need to create or restore a companion for a project. The phrase 'This does not send work to Claude' gives a negative guideline (don't use to send work), but there are no explicit alternatives or exclusion criteria relative to sibling tools like companion_start or companion_resume.

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