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

Annotations already flag destructiveHint=true and openWorldHint=true, but the description earns its keep by explaining why: the DMs 'speak in the user's name', so consent is required, and activation may fail leaving a draft with a stated reason. It also documents the exact message/button sequence and follow-gate branching, which the annotations cannot convey.

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?

Four short paragraphs, front-loaded with the trigger and target, then consent, then flow, then failure recovery. Dense but each paragraph adds a distinct concern; the repeated language reminders echo schema text rather than adding new information.

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 16-parameter tool with an output schema, the description covers the trigger, the user-consent workflow, the message flow, and the failure path. It leaves out operational details such as account/plan prerequisites or whether an automation is scoped per-post, but nothing required to call it correctly 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 the baseline is 3. The description goes beyond the field-level docs by tying parameters into a temporal flow (opening_message + its button, then link_message + link button + extra_link_buttons, with follow_request_message substituted when follow_gate is true) and by stating the 20-character button-label constraint and language rule.

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 opening sentence gives a specific verb+resource+trigger: 'DM a link to followers who comment `keyword` on the post', with the target being either a `page_id` or a `url`. An agent can distinguish this from siblings like update_automation, activate_automation, and list_automations without opening any 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?

It gives explicit pre-call guidance ('Confirm the post, keyword and messages with the user before calling this') and routes to a sibling on failure ('fix that, then activate_automation; never create a second one'). It stops short of naming update_automation as the alternative for an existing automation, so the when-not-to-create case is only implied by 'never create a second one'.

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