Register a signed-in Redfin session

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

Annotations only declare write/idempotent/non-destructive. The description adds substantial, non-obvious behavior: re-registration updates rather than duplicates, it returns a session_id, mark_active acts in the same call, and critically the registry is inert — it does not redirect which account requests use because calls follow whichever tab the ContextMint Bridge extension is signed into. That is exactly the kind of context an agent would otherwise get wrong.

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?

Front-loaded with the core action, then layered with the two clarifications that actually matter (label-only semantics, tab-based auth). It is dense but every sentence earns its place; only the closing sentence is slightly sprawling relative to the rest.

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?

No output schema exists, yet the description still names the return value (session_id). For a mutation tool whose safety profile is covered by annotations, it covers the behavioral and authentication model fully enough for an agent to call it correctly and interpret the result.

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 account_identity, mark_active, and auth_expires_at are already fully documented in the schema. The description restates mark_active ('mark it as the current account in the same call') and mentions the session_id return, adding only marginal meaning over the structured fields. Baseline 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?

States a specific verb+resource: 'Record (or refresh) which Redfin account the signed-in session belongs to, keyed by account_identity.' It further distinguishes itself from the sibling redfin_set_active_session by explaining that the registry is 'a label only' and does not change which account requests use, so an agent can tell the two apart without opening either schema.

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?

Gives clear context: re-registering the same identity updates the existing entry, mark_active marks it current in the same call, and it explicitly warns that to read a different account you must sign the browser tab in. This is strong when-to-use guidance, but it never names the obvious alternative (redfin_set_active_session) or states when-not to use this tool, so it stops short of the top score.

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