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

The description's font/typography note is genuinely useful behavioral context beyond the annotations: it warns that plain-text glyph rendering is unreliable and instructs the agent to point users at the canonical web link. But the description frames this as a pure retrieval operation ("Look up") while annotations declare readOnlyHint=false and destructiveHint=true, a direct inconsistency about the operation's nature that the description never addresses.

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 core purpose is front-loaded in one tight sentence, and the supporting note is set off with a clear "Note:" marker. The note runs slightly long on typography detail, but every clause carries actionable information for the agent.

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 simple two-parameter lookup with no output schema, the description covers the query surface, the glyph-rendering caveat, and the recommended user-facing follow-up. The main omission is any statement about the result set shape or why the tool carries destructive/idempotent annotations that conflict with a lookup operation.

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 both parameters are already documented in the schema, establishing the baseline of 3. The description adds only marginal meaning, notably that "radical" is a valid query axis, which the schema expresses instead through the category filter example.

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 first sentence gives a specific verb ("Look up") and a precisely scoped resource ("indigenous Nsịbịdị ideograms, root radicals, and compound symbols"), plus the four lookup axes. The Nsịbịdị domain implicitly separates it from siblings like search_dictionary or lookup_name, but no sibling is named 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?

Usage is implied by the lookup framing and the enumerated query axes, so an agent can infer when to reach for it. However, there is no explicit when-to-use/when-not guidance and no mention of how it differs from search_dictionary or search_cultural_archive, which are the closest alternatives.

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