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

With no annotations, the description carries the full burden, and it does disclose useful data semantics: officetype holds raw space-separated NECA Tariff 4 office-capability codes and is explicitly not the equipment model in switchtype — a real footgun an agent would otherwise hit. It omits behavior on invalid/not-found CLLI codes and any rate-limit or permission notes, 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?

Four sentences, front-loaded with the purpose before the usage triggers and the alternative routing. The officetype/switchtype sentence is long but earns its place as the only disambiguation of a confusing field; nothing here is filler.

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?

No output schema and no annotations, so the description must carry the load, and it does provide the key return-field caveat plus boundary conditions against get_exchange. It stops short of describing the broader response shape or failure modes, but for a single-record lookup it is close to sufficient.

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%, so both clli and api_key are already documented, and the description's contribution is only restating the 11-character CLLI requirement. The detailed field explanation (officetype vs switchtype) concerns the response, not the inputs. Baseline 3 is correct.

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 ("Fetch") and precise resource ("central-office/switch detail") scoped to exactly one 11-character CLLI code. The scope is narrow enough that an agent can distinguish it from sibling lookups like get_exchange or get_ocn_profile without reading either schema.

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?

Explicitly enumerates the trigger conditions (switch, wire center, location, equipment/switch type, LATA, tandem, point code, English name) and then redirects to a named alternative: "For prefixes served by a switch, start with get_exchange or related prefix-listing tools." Both when-to-use and when-to-go-elsewhere are covered.

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