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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral context: results include per-hack fields, copy counts, counts of users who read a message in the last 30 days ('working') versus stopped matching ('stopped'), and an example message. That tells the agent how to interpret and rank results, which annotations cannot convey.

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 sentences, front-loaded with the action and query modes, then return contents, then the usage rule. Every sentence carries information, though the return-value sentence is dense and could be split for readability.

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, so the description correctly takes on the burden of describing return contents (fields, usage counts, working/stopped counts, example message). Combined with the when-to-use rule and the single well-documented parameter, an agent has enough to call and interpret it; only the absence of explicit alternatives keeps it from 5.

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 the baseline is 3, but the description adds a concrete example value ('like chase.com') that clarifies the expected domain format and reinforces that name matching is also supported. It does not add syntax rules beyond the schema's 'Leave out for the most used', so it stays below 5.

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 ('Searches the hacks people share with the community') and immediately narrows the query modes to sender or name. This clearly separates it from siblings like get_community_hack, use_community_hack, and share_hack, which operate on a single hack rather than searching the shared pool.

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 an explicit when-to-use rule: 'Before building a hack for a sender, look here: a shared one that's working saves the person an AI suggestion.' That is a concrete decision rule tied to a workflow. It stops short of naming the alternative tools (e.g. suggest_hack, use_community_hack) for the case where no working shared hack exists, so it is not a full 5.

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