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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered structurally. The description adds genuinely new behavioral context: per-post billing ('1 credit + 1 credit per post returned') and the fact that each result embeds the quoted post. Missing is anything about error conditions or rate limits, so this is solid but not exceptional.

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 and return shape, then value proposition, then cost, then pagination — a sensible priority order. The pagination instruction is stated twice ('Paginate with meta.nextCursor' and 'When meta.nextCursor is set, call again...'), which is the one redundant element.

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, yet the description covers the key return contract (quoting posts, each with `quotedPost` embedded, `meta.nextCursor` for paging) as well as cost per call. For a single-resource, four-parameter read tool, an agent has everything needed to invoke and cost-estimate it correctly.

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%, so the schema already documents id, sort, limit and cursor thoroughly. The description repeats the cursor round-trip ('call again with cursor set to it') and names meta.nextCursor, which mildly links the input to the response shape, but adds no syntax or constraints the schema lacks — 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?

States a specific verb and resource ('Get posts quoting an X post') and immediately disambiguates from the nearest sibling by contrasting with replies ('discussion beyond its replies'). An agent can distinguish it from get_x_replies and get_x_post without opening any schema.

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 a clear use case ('tracking how a post is being discussed beyond its replies') and implies the reply-thread alternative. It stops short of an explicit when-not-to-use or a named sibling to prefer, so it falls short of a 5.

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