session_start

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, but it provides none. It does not mention side effects (e.g., whether it creates a new connection, replaces an existing session, or requires a client), authentication needs, or what happens if the session ID already exists.

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 short but redundant: 'Start new session.' and 'Starts a session for the given session ID.' convey the same information twice. This wastes space that could have been used for useful context.

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 session lifecycle tool with no annotations and no output schema, the description should explain what starting a session entails (e.g., creates a connection, returns a session status). It only states the basic action and parameter, leaving important contextual gaps for an agent to invoke it correctly.

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 fully covers the single parameter sessionId with a description and example, so the description's reference to 'the given session ID' adds no new meaning. Baseline 3 is appropriate given 100% schema coverage.

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 action ('Start new session') and the resource ('session'), using a specific verb. It distinguishes itself from sibling tools like session_stop and session_restart by implying a fresh start, though it does not explicitly differentiate from session_restart.

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?

There is no guidance on when to use this tool versus alternatives such as session_restart or session_stop, and no mention of prerequisites or context. The description only states what the tool does without any usage direction.

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