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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description still adds real value beyond them: 'customer-safe' signals that internal data is redacted and 'email-verified application session' signals an authorization/scoping requirement. It does not cover behavior for invalid or expired tokens, which keeps it from a 5.

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?

One front-loaded sentence with no filler; the scope qualifier ('one email-verified application session') comes immediately after the resource. Nothing is redundant with the schema or annotations.

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?

An output schema exists, so return-value documentation is unnecessary, and the description covers resource, scope, and safety posture. The remaining gap is operational: no mention of error or expiry behavior for the token in a tool whose only input is that token.

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 0%, so the single parameter is undocumented in the schema. The description partially compensates by characterizing the session as 'email-verified' and 'application' scoped, but it does not explain the sessionToken's format, origin, or what happens if it is stale.

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 ('Read') and resource ('viewing proposals and confirmed viewing state'), scoped to one session. It clearly reads as the read counterpart to the sibling write tools viewings.propose_availability and viewings.respond_to_proposal, though it never names those siblings explicitly.

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 phrase 'for one email-verified application session' implies when it applies, but there is no explicit when-to-use guidance, no stated preconditions for obtaining the sessionToken, and no reference to alternatives like viewings.propose_availability when the agent actually wants to act rather than read.

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