search_calls_by_number

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

No annotations are present, so the description carries the burden. It discloses key behavior: last-10-digit matching, normalization to digits-only, a 7-digit minimum to avoid false positives, account_id auto-resolution, and default lookback window. It doesn't mention pagination/rate limits, but this is a read/search operation and output schema covers returns.

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 one-sentence purpose, followed by a tight Args block. No filler; each line conveys a distinct constraint.

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 4-parameter search tool with no annotations and an output schema, this is nearly complete: purpose, all parameters, matching behavior, and lookback are covered. It would be slightly stronger with an explicit alternative/when-not-to-use, but nothing essential to invoke it 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?

Schema coverage is 0%, but the description documents every parameter with operational detail: phone_number format and minimum length, account_id auto-resolution, company_id as optional filter, and days as lookback with default. This is exactly the compensation needed.

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 the exact operation ('Find calls from/to a specific phone number') and resource ('calls'), plus matching semantics (last 10 digits). This distinguishes it from list_calls/get_call at a glance.

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?

Implies usage when an agent has a phone number and needs related calls, and describes input constraints (at least 7 digits). However, it does not explicitly name sibling alternatives like list_calls/get_call or state when not to use them.

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