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

Annotations already flag destructive+idempotent+openWorld, and the description adds real substance beyond them: it says the call REPLACES stored settings, that enabled=true makes the bot answer live comments, that enabling is charged once per post, and that yt caps at 20 replies/channel/day. That is exactly the operational context annotations can't 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 the [write] marker and the core verb, and nearly every clause carries information (platform restrictions, rate limit, billing). It is, however, extremely dense — a single paragraph mixing identifier syntax, nested-object schema, and business rules — which raises misread risk.

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 destructive write tool with a 0%-documented nested parameter and no output schema, the description covers identifiers, payload shape, per-platform constraints, rate limits, billing, and prerequisites. Nothing an agent needs in order to call it 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 description coverage is 0% and auto_reply is an opaque nested object, so the description carries the full burden — and it does, enumerating mode values (MATCH|AI|MATCH_AI) with their semantics, rule shape, fallback, and ai provider fields, plus the platform enum ig|fb|tw|tt|yt|li|th. This is far beyond what the schema provides.

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 the specific verb and resource ("[write] Save the comment auto reply settings of one post") and explicitly scopes it to a single post, distinguishing it from set_account_auto_reply. Also notes the per-platform identifier variants (post_id/post_uuid, yt_video_id) upfront.

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?

Explicitly routes to siblings: "check it first with test_post_auto_reply" and "Read the current settings with get_post_auto_reply". It also tells the agent when the action is charged vs free, which is genuine decision-relevant guidance for when to enable.

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