enrich_phone

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

With no annotations, the description carries the transparency burden and does disclose the core behavior: normalizing, validating, detecting line type, and returning a structured dict. A small inconsistency exists because it says 'returns the carrier region' while the documented return keys are country_code and line_type, not an explicit carrier_region key.

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 summary is one tight sentence, followed by concise Args and Returns sections. There is no filler or repetition, and the most important information is front-loaded.

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 no annotations and no output schema, the description covers purpose, parameters, and the returned dictionary well. It falls slightly short on edge-case behavior, such as exactly what happens for invalid numbers beyond a 'valid' flag, and it never fully reconciles 'carrier region' with the listed return keys.

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 0%, so the description must compensate, and it does. It explains that phone accepts any format with illustrative examples, and country_hint is documented as an ISO 3166-1 alpha-2 code with default 'US' and the rule for when it 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?

The description opens with a specific verb and resource: 'Parse and validate a phone number.' It then names concrete enrichments (E.164 normalization, line type detection, carrier region) that distinguish it from sibling tools like enrich_email and enrich_address.

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 clearly establishes the tool's context: it is for processing phone numbers, not email addresses, IPs, or other entities. It does not explicitly name alternatives or exclusion conditions, but the purpose sentence and sibling set make when-to-use obvious.

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