create_session

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

With no annotations provided, the description carries the full burden. It discloses the expected output (sessionId, playerUrl, sessionStatus), the initial state (CREATED) and transition to RUNNING, and the PII constraint on subjectId. It does not cover error cases or authorization requirements, but the key behavioral traits are clearly described.

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 relatively concise at three sentences, but the third sentence has awkward grammar ('which is the link' could ambiguously refer to playerUrl or sessionStatus). It front-loads the core action and prerequisites, making it easy to scan. Minor redundancy exists but overall it is well-structured.

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?

Despite no output schema, the description explains the return values and the session lifecycle, which is essential for an AI agent to understand the tool's behavior. It also gives context about how to obtain the flowId. While it omits error handling and edge cases, the tool is relatively simple and the description is sufficient for correct use.

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 description coverage is 100%, and the description repeats the schema's parameter explanations (e.g., flowId from list_flows, subjectId as non-PII reference) without adding significant new detail. The locale parameter is not mentioned in the description, so the description does not augment the schema meaningfully. Baseline of 3 is appropriate.

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 tool's purpose with a specific verb and resource: 'Create a new identity-verification session.' It also specifies the context (for a given flow) and differentiates from sibling tools (list_flows, list_sessions, get_session) by focusing on creation rather than listing or retrieval.

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 provides clear context by indicating that flowId comes from list_flows and that subjectId is your internal reference, implying the prerequisite steps. However, it does not explicitly mention when not to use this tool or alternative options, so it earns a 4 rather than a 5.

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