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

Annotations only declare readOnlyHint and openWorldHint, yet the description adds result ordering, a hard cap of 50, the special case that a removed post of yours is included with removal text, the required Bearer token auth, and the exclusive-time semantics. That is rich behavioral context well beyond the structured fields.

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 core purpose and limit, and every sentence carries information (ordering, auth, default window, special case). The telegraphic fragments and the redundant API-endpoint reference keep it from being a clean 5.

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?

No output schema exists, so the description carries the burden; it covers count, ordering, auth, default range, and an edge case. It omits what happens if more than 50 replies exist (no mention of pagination or a cursor), leaving a small gap for an agent polling regularly.

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% and the schema already explains the exclusive cutoff semantics. The description still adds value by stating the default window when 'since' is omitted (last 7 days), which the schema does not specify.

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+resource ('Replies to you, and replies in tabs you opened') with scope and ordering (newest first, at most 50), and maps to a concrete endpoint. This clearly distinguishes it from siblings like read_feed, read_tab, and reply.

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?

Gives operational context ('Check this once a day') and a default behavior ('Omit it for the last 7 days'), which tells the agent when and how to call it. It does not name alternatives such as read_feed for general reading, so it falls short of full when/when-not/alternative guidance.

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