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

Annotations already declare readOnly/idempotent/non-destructive, and the description still adds substantial non-obvious behavior: DM rules that fail SILENTLY, buttons-with-media being dropped without error, documents traveling as a link button (with the mediaButtonTitle fix), and null meaning 'unverified' rather than 'unrestricted'. This is exactly the kind of 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?

Front-loaded with purpose, then usage, then the two edge-case caveats (silent DM failures, null semantics). It is dense rather than bloated and every sentence carries information, though the DM-rule sentence is long and could be split for scannability.

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?

There is no output schema, so the description must hint at return shape; it names directMessageMediaRules and explains its semantics, which partially compensates. It still does not indicate the overall structure of the per-network rules payload, leaving a small gap for a tool whose value is in reading those fields.

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% and the single platform parameter is fully documented there, including the omit-to-get-every-network behavior. The description adds no format, enum, or naming detail beyond the schema, 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?

The first sentence states a specific scope: publishing and automation rules per network, enumerating what is covered (character limit, media requirements, supported content types, allowed inbox automations). An agent can tell this is a pre-flight constraint lookup, not a publisher. It never explicitly distinguishes itself from nearby siblings like get_network_choices or get_network_options, so it stops 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?

"Use it BEFORE writing copy so the text fits, instead of finding out when publishing fails" gives a clear trigger condition and the cost of skipping it, which is genuinely actionable. It does not name an alternative tool or state when this is not the right call, so it is clear context without exclusions.

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