send_message

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

Annotations already declare write, non-idempotent, non-destructive, open-world behavior, so the description doesn't need to restate the safety profile. It adds the 4096-character delivery constraint and supported formatting modes, which matter in practice, but says nothing about notification behavior, rate limits, error conditions, or what is returned on success.

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?

Two sentences, no filler: capability first, supported formats second, hard limit and fallback third. Every clause carries information an agent needs before calling.

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 17-parameter tool with no output schema, the description covers only the two required fields and the size limit. An agent gets no help with the fifteen optional parameters, threading, reply targeting, or silent/protected delivery, which is a substantial omission for a tool this wide.

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 description only touches text length and the parse_mode enum, both of which are already explicit in the schema. With 17 parameters at 53% coverage, many fields (message_effect_id, business_connection_id, callback_query_id, reply_parameters, protect_content) remain unexplained, and the description does nothing to close that gap. Mid coverage puts the baseline at 3, and the text adds essentially nothing beyond it.

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?

States a specific verb and resource ("Send a text message to a chat"), which cleanly separates it from the media-sending siblings like send_photo or send_document. It also names send_rich_message as the path for long posts, so the boundary with the closest sibling is drawn.

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 one explicit routing rule: posts over 4096 characters should go to send_rich_message. There is no guidance on when to prefer this over media senders, reply/edit flows, or draft tools, but for the core text-send case the usage condition is clear.

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