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

Beyond the readOnly/non-destructive annotations, it discloses negative capability information an agent genuinely needs: the mode=default voice-bot prompt is 'not available through the current public MCP', and mode=unavailable means a binding could not be resolved. It also defines callAgent=null and enabled=false semantics. No mention of pagination or ordering, which keeps it out of the top band.

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?

Purpose is front-loaded in sentence one, and the remaining sentences are dense but each carries distinct field semantics. It reads as one long block rather than a scannable list, which slightly hurts structure, but there is little filler.

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?

With an output schema present, return-shape description is not required, yet the description usefully disambiguates the mode enum values and null/disabled cases that a structural schema alone would not convey. Pagination and ordering behavior remain unstated.

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 tool takes zero input parameters, so the baseline is 4. The description adds output-field semantics instead, which is value beyond the empty 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 first sentence states a specific verb and resource ('List connected WhatsApp accounts') and even scopes it ('with distinct TEXT CHAT and CALL agent bindings'). It does not, however, differentiate itself from nearby siblings such as list_whatsapp_agents, list_phone_numbers, or list_inbound_assistants, so an agent cannot fully route on the description alone.

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?

It routes the agent to concrete follow-up tools ('textAgents contains IDs for get/update_whatsapp_agent', 'inboundAssistantId for get/update_inbound_assistant') and adds a caution ('Never choose an agent by name alone'). It stops short of explicit when-to-use/when-not versus the sibling list_* tools.

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