search_calls_by_number

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

With no annotations provided, the description bears full burden. It discloses normalization of phone number, last-10-digit matching, minimum 7-digit requirement, and auto-resolution of account_id. This provides good behavioral insight, though it does not explicitly state if the operation is read-only.

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?

The description is well-structured with a clear heading and Args section. It is concise (6-7 lines) with no redundant information. Every sentence adds value.

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?

Given the output schema exists, return values are not required. The description covers all input parameters and key behaviors (matching logic, normalization, defaults). The tool's role among 45 siblings is clear.

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 fully compensates: explains phone_number normalization and min digits, account_id auto-resolves, company_id optional, and days default. Nearly all parameter semantics are covered beyond 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?

The description explicitly states 'Find calls from/to a specific phone number' and explains the matching logic on the last 10 digits. This clearly distinguishes it from sibling tools like 'get_call' (single call) and 'list_calls' (unfiltered listing).

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 description provides context for when to use (searching by phone number) and explains input flexibility (any format, last 10 digits). However, it does not explicitly state when not to use this tool or mention alternatives for scenarios like broader searches.

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