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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety and idempotency are covered structurally. The description adds the pagination behavior, which is genuine extra context, but says nothing about result ordering, match thresholds, or empty-result behavior.

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?

A single sentence that front-loads the action and resource and packs the default/override hash-type rule into a trailing clause. No filler, nothing to trim.

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 annotations cover the safety profile. What remains thin is parameter coverage: page/limit are undocumented and hash_value's expected encoding is unstated, which matters for a search tool where a malformed hash silently yields no results.

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 0%, so the description must compensate, and it does cover two of four parameters: hash_value (the favicon hash to match) and hash_type (mmh3 default vs. MD5). It does not explain page/limit semantics beyond the word 'paginated', nor the expected format of hash_value.

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 ('Search scans by favicon hash') plus the two supported hash algorithms, so the agent knows exactly what is being queried. However, it never distinguishes itself from the near-duplicate sibling 'search_favicon_mmh3' or from 'get_favicon', which is a real ambiguity given the sibling list.

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 explains the mechanism but gives no when-to-use guidance, no exclusions, and no routing to alternatives such as search_favicon_mmh3 (which appears to cover the same mmh3 case). The agent must infer the selection context entirely.

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