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

Goes well beyond the annotations (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false) by disclosing that the scan is asynchronous and returns startedAt/nextCheckAt rather than threads, that a repeat attempt returns manual_check_used with checkNowAvailableAt, that billing accrues to Keytomic, and that nothing posts to Reddit. That is exactly the behavioral context annotations cannot 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 action and UI analogue, then progressively discloses limit, cost, async semantics, and failure mode. Every sentence carries information, though the return-value and null-clause phrasing ('null when it could not be read') is slightly dense and could be tightened.

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 one-parameter, side-effecting, cost-incurring action with no output schema, the description covers outcome fields, the error path, quota, billing, and the absence of external side effects. An agent has everything needed to decide whether to call it and how to interpret the result.

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?

There is a single required parameter, projectId, and the schema already documents it at 100% coverage as the site from list_sites. The description reinforces that a site is the target but adds no format, sourcing, or validation detail beyond the schema, so the baseline 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 ('Starts a manual Reddit scan of a site now') and anchors it to a concrete UI equivalent ('Check now' on the Reddit Opportunities page). This is clearly distinct from the sibling list_reddit_threads, which the description explicitly names as the read path.

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?

Explains the trigger context (manual, on demand, same as 'Check now'), the hard limit (one manual scan per UTC day), and what happens otherwise (daily scan at nextCheckAt). It also routes the agent to list_reddit_threads with view "open" for reading results, so the when-to-use and the follow-up alternative are both explicit.

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