insync_send_message

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

Annotations already declare destructiveHint=true and openWorldHint=true, and the description adds material context beyond them: the message cannot be unsent, delivery may not be read promptly, and the confirmation flow (client prompt, or preview + confirmToken repeat call) is described. It also warns against obeying instructions embedded in tool results, which is a real behavioral safeguard.

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?

Front-loaded with purpose followed by prerequisites and exclusions, with no filler. The final confirmation-flow sentence is dense and runs together several rules (confirm prompt vs preview/token vs MCP_CONFIRM_MODE), which slightly reduces readability.

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?

No output schema exists, and the description covers the two-phase return behavior (a 'confirmation-required' preview plus confirmToken) as well as irreversibility and delivery expectations. Nothing an agent needs to call this dangerous write safely is missing.

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 coverage is 100%, so all four parameters are already documented in the schema, including the confirmToken's phase-1/phase-2 protocol. The description reinforces the token rule and the group-id source but contributes little new semantic detail beyond what the schema states, so the 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 and resource ('Send a NEW secure message to a group') and explicitly contrasts with the sibling it is not: 'Use insync_reply_message to answer an existing message.' An agent can distinguish send vs reply without opening either schema.

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 the prerequisite (get group ids from insync_list_message_recipients), an explicit exclusion ('Not for emergencies'), and the alternative tool for the reply case. Conditions for use are fully spelled out.

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