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

Annotations are minimal (no readOnlyHint, destructiveHint false). The description compensates by disclosing that repeating the poll is safe and does not trigger another phone call, and by setting explicit prohibitions (never ask for phone number, never request separate platform authorization, never begin_agent_link again). It also explains the sessionId authentication behavior. No contradiction with annotations; the safety guarantee aligns with destructiveHint false.

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 lengthy but every sentence carries crucial operational guidance: aliases, safety, retry conditions, and prohibitions. It is front-loaded with the core action and then expands into necessary context. While not terse, the density of actionable instructions justifies the length; a slightly tighter structure could remove redundancy (e.g., 'Never' list repeated), but it remains effective.

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 4 parameters, no output schema, and the need to coordinate with other tools, the description covers all necessary operational context: which parameter to prefer, how to handle aliases, what to do on success (pass partner_session_id), when to retry, and what to avoid. An agent can invoke this correctly without additional information.

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 all parameters have descriptions. The tool description adds significant value by clarifying that attemptId and sessionId are aliases for linkSessionId, by explaining the preference for linkSessionId, and by detailing when sessionId should be passed (when no Authorization Bearer). This goes well beyond the schema's static descriptions.

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 ('Poll') and a specific resource ('secure Dixy sign-in link') with clear context ('after the owner completes it in the browser'). It distinguishes itself from the sibling poll_agent_link by the Dixy-specific scope and references to start_dixy_call_auth. The purpose is unambiguous.

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?

Explicitly states the preferred parameter (linkSessionId from start_dixy_call_auth) and acknowledges aliases. Provides clear conditions: when to retry (if AGENTPAY_API_KEY required and sessionId exists), when not to act (never begin_agent_link again, never ask for phone number or separate authorization), and post-conditions (pass partner_session_id as dixySessionId). This is far beyond typical usage guidance.

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