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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior, so the bar is lower. The description adds a genuinely important behavioral trait beyond them: results are drawn from a live ~20-item rolling window, meaning the same query can return different results over time despite the idempotentHint, and there is implicitly no pagination or deep history.

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, each carrying distinct information — source, match fields, and window scope. The most important constraint (ephemeral rolling window) is front-loaded in the same sentence as the purpose rather than buried.

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 two-parameter, read-only search with no output schema, the description covers purpose, source, matching semantics, and the key limitation. The only gap is that it does not characterize the shape of a returned release (fields available), which an agent might want before calling.

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. The description goes beyond the schema by specifying what 'query' is matched against (headline, issuer name, excerpt), which the schema only describes as 'Company name or keyword to match.' The limit parameter's meaning is left entirely to the schema.

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 ('Keyword/company search over GlobeNewswire's current public-company feed'), names the fields matched (headline, issuer name, excerpt), and pins the scope to a live rolling ~20-item window. That scope statement cleanly separates it from archive-oriented siblings like archive_compare and from get/latest_releases.

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 clear usage context by declaring the search only covers the live rolling window and explicitly excludes historical archive use ('not a historical archive'). It stops short of naming which sibling to use for historical or single-release lookups, so it is clear context with an exclusion but no explicit alternative routing.

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