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

Annotations already cover read-only, idempotent, non-destructive, open-world behavior. The description adds valuable context beyond that: a concrete cost model ("1 credit + 3 credits per post returned") and pagination continuation behavior via meta.nextCursor. It does not cover auth expectations or result ordering defaults, but the core operational traits are disclosed.

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?

Three tight sentences: purpose first, the search_reddit comparison and use condition second, then cost and pagination. No wasted clauses, and the most important scoping information is front-loaded.

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 read-only search tool with rich annotations, 100% schema coverage, and no output schema, the description supplies the missing operational details an agent needs: cost implications and cursor-based pagination. Nothing essential to correct invocation is absent.

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%, so every parameter is already documented in the schema. The description only adds a high-level "Same fields as search_reddit" reference and pagination guidance, not per-parameter meaning beyond what the schema already provides. Baseline 3 is appropriate.

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 description names a specific verb and resource ("Search public posts inside one subreddit") and explicitly scopes it against siblings by saying it uses the same fields as search_reddit but applies when the community is already known. An agent can distinguish this from search_reddit and search_subreddits immediately.

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?

It gives an explicit decision rule: use this when the subreddit is known, implying search_reddit when it is not. It also instructs exactly what to do for pagination ("When meta.nextCursor is set, call again with cursor set to it"), leaving nothing to inference.

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