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

Annotations only declare readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description adds two genuinely useful traits beyond that: the token TTL (~30 minutes) and the fact that the server does not retain the token. It still omits failure modes (invalid signature, expired nonce, replay handling).

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?

Two tight sentences, front-loaded with the action and followed by the one caveat an agent most needs (TTL and non-retention). Nothing wasted.

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?

There is no output schema, so the description correctly states what is returned (the token) and its lifetime. For a 3-required-param auth tool this covers the essentials, though error behavior on a bad signature or stale nonce is left unstated.

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 only 33%, so the description would need to compensate, but it barely does. It references the signed challenge (mapping loosely to signature/nonce) without explaining the nonce's role or how botId links to the challenge; parameter names are self-describing, so this is minimal but not harmful.

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 gives a specific verb and resource: exchange a signed challenge for a Trust session token. It is clearly distinguishable from siblings like trust_get_challenge and trust_verify_signature, though it never names those alternatives explicitly to route the agent.

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?

Usage is implied rather than stated: 'Exchange a signed challenge' tells the agent a challenge must already exist, but it does not say to call trust_get_challenge first, nor when this step is required versus optional in the auth flow.

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