Register a signed-in Redfin session

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

The description adds behavioral context beyond annotations: it states that re-registering updates rather than duplicates, and explains the default active session behavior. Although annotations include 'idempotentHint: true', the description clarifies the update semantics. No contradictions with annotations.

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 four sentences, each serving a purpose: registration action, update behavior, return value, and active session handling. It is front-loaded with the key verb and resource, and no extraneous 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?

Given the simplicity of the tool and the absence of an output schema, the description covers all necessary aspects: registration/refresh mechanism, session identity, active session management, and return value. It is fully adequate for an AI agent to use 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?

Schema coverage is 100%, but the description significantly adds meaning: it explains that 'account_identity' is the key for session identity, clarifies the effect of re-registration, and describes how 'mark_active' works. It also explains the return value 'session_id' which is not in the schema.

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 that the tool registers or refreshes an authenticated Redfin session, using specific verbs and resource identification. It distinguishes itself from sibling tools like 'set_active_session' and 'get_session_context' by focusing on session creation/update and identity keying.

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 on when to use: for registering or refreshing sessions to route per-tool calls. It explains the behavior of re-registering and setting active session, but does not explicitly state when not to use or directly compare to the sibling 'set_active_session' tool.

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