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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, yet the description still adds substantive behavior: no continuation cursor exists, limit caps one relevance-ranked set rather than acting as an offset, no matches yields an empty set while invalid queries return errors, reads are unauthenticated and uncached, and there is a 60 req/IP/min budget with 429 Retry-After. None of that is recoverable from the annotations or schema.

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 compact paragraphs ordered by importance: purpose and routing first, then query syntax, then result/limit semantics, then operational constraints. Every sentence carries distinct information; nothing restates the name or the 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?

Output schema exists, so return shape need not be described. The remaining agent-facing unknowns for a public search tool — pagination absence, empty-vs-error outcomes, auth, caching, and rate limits — are all covered.

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 already 100%, so the baseline is 3, but the description earns more by explaining query syntax the schema omits ('Abyssal demon' 'drop' requires both phrases, intitle: for titles, prefix:Category: for categories) and server-side URL encoding, plus clarifying that limit is a relevance-ranked cap rather than an offset. This directly changes how an agent constructs calls.

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?

Opens with a specific verb and resource ('Find RS3 Wiki sources for items, NPCs/monsters, quests and guides') and immediately scopes the domain. It names the three sibling tools that cover adjacent needs, so an agent can distinguish search_wiki from get_wiki_page_content, lookup_item and get_item_details without opening a schema.

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?

Explicitly routes: use get_wiki_page_content for reviewed text, lookup_item for GE identities, get_item_details for catalogue records. That names the alternatives and the condition that selects each, rather than leaving usage to inference.

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