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

Annotations already establish the safe read-only, idempotent profile, and the description adds genuinely useful context beyond them: what fields come back, that passwords are never returned, and that a boolean '<field>_set' signals password presence. This security detail is not derivable from the annotations.

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 purpose and the id source, then the return details. It is dense but each clause earns its place given there is no output schema; the long parenthetical field enumeration is borderline but justified.

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?

With no output schema, the description correctly compensates by summarizing the returned fields, including type-specific configuration and the password-redaction behavior. An agent has everything needed to call it and interpret the response.

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% on a single required 'id' parameter, so the schema already carries the semantics; the description only restates that the id is the uuid from list_sms_trunks. Baseline 3 applies when the schema does the work.

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 (Return full details) and resource (SMS trunk) scoped to a single id, and explicitly names list_sms_trunks as the source of that id, which cleanly separates it from the list sibling and from create/update/delete_sms_trunk.

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 parenthetical '(the uuid returned by list_sms_trunks)' tells the agent how to obtain the argument, giving clear usage context. It stops short of explicit when-not guidance or naming the alternative getters (get_trunk, get_did_had) it should not be confused with.

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