Send Message

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

Annotations already declare readOnlyHint=false, idempotentHint=false, openWorldHint=true, so the safety profile is covered. The description reinforces non-idempotency in plain language ('calling twice posts twice') and notes it posts 'as the authenticated user', adding auth context, but says nothing about failure modes, rate limits, or the open-world/external nature beyond the annotation.

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?

Three short sentences/paragraphs, front-loaded with purpose, then prerequisites, then the reply variant. No filler and no repetition of schema details.

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?

An output schema exists, so return values need no explanation. For a non-idempotent send tool, the description covers target-dependent ids, the double-send hazard, and the reply option — everything an agent needs to invoke it correctly.

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 100%, so all four parameters are already documented, including the conversation oneOf shape and the image_url restriction. The description only restates the reply_to_message_id usage and id provenance, adding little beyond the schema's own text; baseline 3 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?

States a specific verb ('send') and resource ('a message to a GroupMe group or direct-message chat'), covering both target types. An agent can immediately distinguish it from siblings like read_messages or list_conversations, which are only mentioned as id sources.

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?

Explicitly says when to use it ('once you know where to send', ids from list_conversations), warns that each call posts a new message, and names the alternative path for replies ('to reply to a specific message, pass its id'). Prerequisite ordering and the reply use-case are both spelled out.

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