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

Annotations only cover the safety profile (readOnly, idempotent, non-destructive). The description adds substantial content-level transparency: the returned field groups, that E911/CNAM are included, that all amounts are USD, and critically that related entities come back as id+name only. That last point is a genuine behavioral trait an agent could not infer.

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 dense sentence, but it is front-loaded with the operation and then groups the return fields logically (number/location, status, routing, capacity, billing, regulation, E911/CNAM). Given the absence of an output schema, the length is justified, though the run-on structure could be broken into clauses.

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 must carry the entire contract for return values, and it does so exhaustively — enumerating every field group plus the id+name abbreviation rule for related entities. Nothing an agent needs to invoke or interpret this read correctly is missing.

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?

Only one parameter and schema coverage is 100%; the schema already states it is the DID UUID from list_dids. The description's parenthetical repeats that verbatim, adding no syntax or format detail beyond the schema, so the 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 (return full details) and resource (one DID) plus the lookup key (id from list_dids). It is immediately distinguishable from list_dids (enumerate), get_did_history (history), and update_did (mutation).

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?

Names the id source (the uuid returned by list_dids) and explicitly routes the agent elsewhere for nested entities ('use the dedicated list tools for their full details'), which prevents the common mistake of expecting full related objects. It does not, however, contrast this tool with get_did_history, so it falls short of a 5.

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