Start session

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

Annotations already declare readOnly=false, idempotent=false, destructive=false, so the mutation profile is covered. The description adds genuine context beyond that: traffic is tagged with the session id while active, and the call returns the new session record. It does not clarify duplicate-name behavior, but it is well above the annotation baseline.

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?

Three tight sentences ordered as purpose, behavior, return value, with no wasted words and the core action front-loaded. Slightly more prose than strictly necessary but every sentence carries information.

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?

With no output schema, the description appropriately states what is returned ('the new session record'). Parameters are optional with sane defaults covered by the schema, and the tagging model is explained, so an agent has enough to invoke it correctly despite the missing when-to-use routing.

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%, so both 'name' and 'environment_id' (including the '0 or omitted = active environment' default) are already fully documented. The description adds nothing about parameters, which is acceptable given the schema does the work; baseline 3 applies.

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?

States a specific verb and resource ('Start a named session') and adds scope detail about traffic tagging, so the agent knows exactly what the call produces. However, it never distinguishes this from closely related siblings like start_capture or attach_environment, so it is clear but not sibling-differentiating.

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 when-to-use/when-not-to-use guidance and no named alternative. The phrase 'so the agent can later replay or compare it' hints at a downstream reason but does not state conditions under which one would choose start_session over start_capture or set up environment attachment first.

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