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

Annotations already cover the safety profile (read-only, idempotent, non-destructive), so the bar is lower. The description adds genuinely new behavior context: the build parameter switches between current and historical result sets, and repeated mentions should not be interpreted as new events or notification changes — a semantic caveat the annotations cannot express.

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 short sentences, front-loaded with what the tool returns and followed by the two interpretive caveats. No filler, though the indented fragment style is slightly harder to scan than a single flowing paragraph.

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?

An output schema exists so return values need no explanation, and the annotations cover safety. The description supplies the non-obvious build semantics and the repeated-mentions caveat, which are the main sources of agent error; only the meaning of the required 'deal' identifier is left unstated.

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 0%, so the description must carry the burden. It explains build thoroughly and implies the date-format for the start/end filing-date range, but the required 'deal' parameter and the exact roles of start versus end are never explained.

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 a specific verb and resource ('Read source mentions by filing date'), plus the notion of coverage and qualifiers. It is clearly distinguishable from get_passage (single passage retrieval) and list_deals, though it never names those siblings explicitly.

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?

It gives concrete operational guidance for the ambiguity-prone choice: omit build for current results, supply build for historical results. It also warns that repeated mentions are not newly occurring events. It stops short of stating when to prefer this over get_passage or list_deals.

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