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

Annotations only declare readOnlyHint=true; the description adds real behavioral detail beyond that: exponential backoff with jitter (2s/1.5x/30s cap), the fact that a timeout returns status "pending" rather than erroring, and that a Proof account is required with explicit auth steps. It does not describe the shape of the terminal-state payload, which is the one remaining gap given there is no output schema.

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 short paragraphs, front-loaded with purpose then the operational caveat then access. Every sentence is load-bearing, though the pre-call reply-text instruction is verbose enough that it could be tightened.

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?

Covers purpose, polling mechanics, timeout/retry behavior, auth gating, and the user-visibility ordering constraint — enough to call it correctly without an output schema. Only the terminal payload contents are left implicit.

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 timeout_seconds description already carries the default/max and the client-timeout warning, so the description adds little parameter-level meaning beyond what the schema provides. 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 (poll) and resource (a session) plus the exact terminal states it resolves on (verified, failed, expired), which separates it from the non-blocking get_session and from the many other wait_for_* siblings that target logins, verifications, or requests.

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 preconditions for calling it (must already be authenticated; must have surfaced the link/SMS/inbox note in the reply text before waiting) and sequencing on timeout. It never names the non-blocking alternative (get_session) or says when not to block, so it stops short of full routing guidance.

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