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

Beyond the annotations (write, open-world, non-destructive), the description discloses substantial behavior: only replies within Meta's 24-hour window, one flow per person at a time, a manual human reply stops the flow, plan gating, and hard limits (40 steps, 6 branch levels, wait caps). This is exactly the extra context annotations cannot carry.

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?

The purpose and constraints are front-loaded before the example, and almost every sentence carries load-bearing information. The inline example is dense and partly restates the schema, but it earns its place by showing the nested structure in use.

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 complex, deeply nested tool with 8 parameters, the description covers triggers, step types, limits, plan requirements, and runtime behavior thoroughly. The only gap is that with no output schema present, the description says nothing about what is returned (e.g. the new automation's id).

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 88%, so the schema already documents the parameters in depth, establishing a baseline of 3. The description adds value beyond that with a concrete end-to-end example of how trigger and steps compose, plus interpolation details ('{username}', '{first_name}'), nudging it to a 4.

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 description gives a specific verb+resource ('Create a DM automation on an Instagram account (or a Facebook Page, Messenger)') and enumerates the trigger types (keyword, any_message, story_mention, story_reply, ref), which implicitly separates it from the comment-triggered sibling create_comment_dm_rule. It never names a sibling explicitly, so it falls just short of a 5.

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?

Usage is implied rather than stated: the description explains what the automation does and the plan requirement ('Needs a Pro or Agency plan'), so the agent can infer this is the tool for setting up DM flows. However, it never says when to choose this over create_comment_dm_rule or update_dm_automation, nor when not to use it.

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