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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering safety. The description adds that it returns a list and notes pagination via cursor, which is useful behavioral context beyond the annotations. It doesn't contradict anything.

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?

The description is two sentences with no fluff. It front-loads the core action and scope, then immediately provides the differentiation and pagination hint. Every word earns its place.

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 a small, fully documented schema and no output schema, the description is sufficient. It covers the key behavior (site-wide search) and pagination. It doesn't detail response fields or error handling, but those are not strictly necessary given the simple nature of the tool.

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 all parameters (query, trim, cursor, sortBy, timeframe) are documented in the schema. The description adds no parameter-specific semantics beyond the schema; it merely mentions keyword and cursor, which are already described.

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 clearly states the tool searches Reddit posts site-wide by keyword, using a specific verb and resource. It explicitly distinguishes from the subreddit-scoped search by naming the sibling tool (reddit.subreddit.search.list), making its scope unambiguous.

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?

The description gives explicit usage guidance: it states the tool is site-wide, not subreddit-scoped, and directs the agent to the alternative for that use case. It also advises using the cursor for pagination, which is a concrete usage instruction.

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