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

The annotations only say readOnlyHint=false, openWorldHint=true, destructiveHint=false, and the description adds substantial behavioral context beyond that: the 24-hour Meta reply window, one flow per person at a time, manual team replies halting the flow, and messages due after the window silently not sending. It also discloses hard limits (40 steps, 6 branch levels, 23h max wait) and the destructive-ish consequence of pausing with active=false.

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?

Purpose and constraints are front-loaded in the first paragraph, and every prose sentence (24-hour window, one flow per person, handoff stops it) earns its place. The trailing example is a large inline JSON blob with elided `[...]` segments that duplicates much of the steps schema, which is the main drag on size.

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, nested, write tool with no output schema, the description covers runtime behavior, limits, and trigger semantics well. It does not say what the call returns (e.g. the created automation id) or what permissions the account needs, which is a modest gap given no output schema exists.

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 already 88% and the nested trigger/steps schemas are exhaustively documented in the schema itself. The long inline JSON example mostly restates the per-step semantics the schema already gives, adding only marginal value in showing how trigger and steps compose. Baseline 3 is appropriate when the schema carries the parameter burden.

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 ('Create a DM automation on an Instagram account (or a Facebook Page, Messenger)') and even summarizes the runtime behavior of the artifact it creates. However, it never names or contrasts with the close siblings create_comment_dm_rule and update_dm_automation, so an agent must infer the boundary from the name alone.

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 only implied through the trigger types and the note that it 'only ever replies to something the person did, within Meta's 24-hour window' — useful scoping, but not stated as when-to-use guidance. There is no explicit when-not or 'use X instead' routing against update_dm_automation or create_comment_dm_rule.

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