project_join

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

Annotations already indicate idempotent and non-destructive. The description adds valuable behavior: joining replaces previous membership, scoped memory and tasks become visible, and default writing behavior. This goes beyond annotations and provides a complete behavioral model.

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 well-structured: a bold summary sentence, then paragraphs explaining behavior and usage. It is clear and concise, though a few sentences could be tightened without loss of meaning.

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 simplicity (one parameter, no destructive actions), the description covers all aspects: what it does, side effects, and when to use. An output schema exists, so return values need not be described. The description is fully adequate.

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 description repeats the parameter description from the input schema ('project_id: The project name to switch to.'). With 100% schema coverage, the description adds no new information about the parameter's meaning or usage, so it's at baseline.

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 'Switch to a project — this becomes your single active project.' It uses a specific verb (switch/join) and resource (project). It distinguishes from sibling tools like project_leave and project_list by explaining the active project behavior.

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 includes 'Join the project you're working in at session start,' implying when to use it. It explains that joining replaces the previous membership, providing context. However, it does not explicitly state when not to use it or mention alternatives, though the context is clear.

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