Contar llamadas (CDR)

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description does not need to emphasize safety. It adds that the tool returns a count, but does not detail the exact return format or any limitations beyond the range. This is minimal added value given the annotations.

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?

A single sentence that is complete, front-loaded with key information, and contains no waste. It efficiently conveys the tool's purpose and optional filtering capability.

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 simple counting tool with no output schema, the description is adequately complete. It identifies the resource (calls) and optional range. The input schema fully documents parameters, and annotations cover behavioral traits. A small improvement could be specifying that the return value is a single integer.

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?

The input schema has 100% coverage with descriptions for all 5 parameters (e.g., 'to': 'Fin en epoch milisegundos'). The tool description only generically mentions 'within a range', adding no new meaning beyond what the schema already provides. Baseline of 3 is appropriate.

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 clearly states the tool returns the total number of registered calls, optionally filtered by a date range. It uses a specific verb-contar (count) and resource (llamadas), and distinguishes from sibling tools like pbx_list_calls that return detailed call records.

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 notes the optional range filtering, implying use when a total count is needed rather than detailed call logs. However, it does not explicitly state when not to use it or name alternatives, though sibling tool names provide context.

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