send_media

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

With no annotations, the description carries the disclosure burden and does well on the critical items: it states the authorization/gating requirement (WHATSAPP_SENDING_ENABLED=true) and two allowlist constraints (source directory, recipient chat). It omits failure behavior, size limits, and whether a sent message can be recalled, so it stops short of full coverage.

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 dense sentence front-loads the action and resource, then appends the hard constraints. No filler, no repetition of the tool name.

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, 0%-schema-coverage mutation tool with no annotations and no output schema, the description covers the path and recipient constraints well but leaves the optional caption undocumented and says nothing about outcomes or failure modes. Adequate but with clear gaps.

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 partially does: filePath gains the crucial 'regular file inside WHATSAPP_OUTBOUND_MEDIA_DIRS' constraint and chatId the 'allowlisted chat' constraint, both absent from the schema. However caption (optional, maxLength 2048) is never mentioned, and the mediaType list merely restates the schema enum.

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?

Specific verb ('send') plus a precise resource enumeration (image, video, audio, document, sticker) and the file source. An agent can tell this is the outbound media path rather than the text path used by send_message, though no sibling is named explicitly.

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?

Gives clear preconditions for use: the file must be a regular file inside WHATSAPP_OUTBOUND_MEDIA_DIRS, the chat must be allowlisted, and WHATSAPP_SENDING_ENABLED=true must be set. No explicit 'use X instead' routing to send_message or download_media, but the operating context is unambiguous.

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