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

The annotations already declare idempotentHint=true, destructiveHint=false and, notably, readOnlyHint=false; the description earns credit for explaining that flag by disclosing the cost model: one credit per search, balance returned, and the same search on the same day is paid only once. That is real context annotations cannot carry. It says nothing about rate limits, failure modes, or what happens when the query exceeds the five-name OR limit, which keeps it below the top of the scale.

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 purpose is front-loaded, but the first sentence is a long run-on enumerating every output column, much of which duplicates the output schema rather than earning its place. The credit/caching sentence is the highest-value line and would benefit from being surfaced earlier and separately from the row-format inventory.

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?

With an output schema present, the description need not spell out return values, and it covers the non-obvious parts: cost and same-day deduplication, sort order (today's list, then score, then newest), and the handoff to `why` and `save_interest`. Remaining gaps are minor, such as empty-result behavior or errors from an over-long OR query.

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 `days`, `limit` and the query grammar (OR, five names max, whole words, `*` suffix wildcard), making 3 the baseline. The description restates `days` scoping and the query semantics but adds no meaning beyond those field descriptions; the wildcard and OR-limit rules are verbatim schema content.

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 states the specific resource and scope: stories from the last `days` whose pieces name the query, one row per story. It also names two downstream siblings (`why` for a row's `item_id`, `save_interest` for examples), which helps an agent place it in the workflow. It stops short of contrasting with other retrieval siblings such as `top` or `morning`, so differentiation is only partial.

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?

Usage is implied rather than stated: you search when you need stories matching a named query, and a returned row's `item_id` routes to `why` while its title feeds a draft via `save_interest`. Those are useful explicit next-step pointers, but there is no when-not-to-use guidance and no comparison against the other read tools in the sibling list.

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