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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description still earns credit by disclosing the result cap and shape ('up to limit passages, each with its document title and document_id'), the single-world scoping constraint, and the retrieval caveat about broad topics. It omits behavior for zero-result searches and ranking details.

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?

Four sentences, front-loaded with the operation and scope, then content coverage, then return shape, then the practical query tip. No filler, no repetition of the title or annotations.

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 no output schema and 0% schema description coverage across 3 params, the description closes most of the gap: return shape, result cap, single-world scope, and query strategy are all stated. A note on empty results or how document_id should feed into read_lore would make it fully complete for chaining.

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 carries the full burden and does add meaning: it gives the limit range (1-12, beyond the bare default of 6) and implies world_id restricts search to one world's library and that query should be a focused question rather than a broad topic. It does not explain what happens for out-of-range limit values or the world_id format.

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 (search/find passages) on a specific resource (one world's Lore Library), and the 'best answer a question or match a topic' framing makes clear this is relevance-ranked retrieval rather than enumeration (list_lore) or full-document fetch (read_lore). It also enumerates the content types it covers (campaign notes, session recaps, setting documents) and the entities it indexes (people, places, factions, history, house rules).

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 concrete usage advice: 'Works best with a focused question; a broad topic may take several searches,' which tells the agent how to phrase queries and that multiple calls are expected. It never names alternatives (list_lore, read_lore) or states when not to use it, so it stops short of explicit routing.

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