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

With no annotations, the description must carry the burden, and it discloses substantive behavior: reverse chronological ordering, that omitting all filters returns most recent changes, that baseline-load events are excluded, and crucially that multi-field changes are returned as one structured old/new JSON entry rather than fragmented per-field results. It omits auth/rate-limit/pagination behavior, 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?

Front-loaded with the purpose, then the use case, then result semantics, then parameter notes — a sensible order. Slightly dense with some overlap between the description and the clli/field schema entries, but every sentence carries information.

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?

For a 9-parameter, zero-annotation, no-output-schema tool this covers the essentials: what changes are tracked, how results are shaped (paired old/new JSON), ordering, and no-filter behavior. Pagination beyond the limit parameter and the api_key handling are left to the schema, which is a minor gap rather than a blocking one.

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 100%, so the baseline is 3. The description does add real semantics beyond the schema for clli (6- to 11-character CLLI or prefix matching switch-related changes) and clarifies that source is a tracked source name, not an archive filename — useful, but the remaining parameters are left entirely to the schema.

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 and resource ('Search TelcoData's tracked source-record changes') plus ordering (reverse chronological), which no sibling tool does — the siblings are point lookups (lookup_tn, get_exchange, get_switch) rather than change history. An agent can distinguish this from every other tool in the list without opening a 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 routes itself: 'Use this for questions about when an NPA-NXX or thousands block changed carrier, OCN, CLLI/switch, assignment status, rate center...' and explains the no-filter fallback. It stops short of naming an alternative tool or stating when not to use it, but the context is clear enough to select it confidently.

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