pi_use_session

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

Annotations already indicate the operation is neither read-only nor destructive. The description adds that it switches state and is meant for resuming work, but it does not explain what happens to the previously current session, whether unsaved state is preserved, or how invalid ids are handled. With annotations present, this is adequate but not rich.

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 concise, with no filler or redundant phrasing. It is front-loaded with the action and object, and the parenthetical adds useful intent without bloating the text.

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 simple one-parameter tool with no output schema, the description conveys the core action and purpose. However, it lacks guidance on where to obtain the session id and what happens to the current session, so an agent may not fully understand the operational context.

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 schema has a single required 'id' parameter with no description, and schema coverage is 0%. The description only indirectly suggests that 'id' identifies the existing session via 'an existing one', but it never explicitly states that id is the target session id, where it comes from, or what format is expected.

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 ('Switch') and clearly identifies the resource ('the current session') and the target state ('an existing one'). The parenthetical 'resume work' reinforces the intent and helps distinguish this from pi_start_session and pi_end_session, though it does not name them explicitly.

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 phrase 'resume work' implies this tool is for switching back to an existing session rather than creating a new one, which gives implicit usage context. However, there is no explicit when-to-use or when-not-to-use guidance, and it does not direct the agent to alternatives like pi_list_sessions or pi_start_session.

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