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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds genuinely useful context beyond that: the ranking comes from a public rule-based score and explicitly excludes ads and user ratings, and results are capped at 5 — both are trust-relevant facts an agent cannot get from structured fields. It does not say what happens with an unknown key or whether fewer than 5 may return.

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 ranking and cap are front-loaded in the first sentence, which is good. But the Korean sentence is a condensed restatement of the same two facts rather than added information, roughly doubling the text without increasing what the agent learns.

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 read-only lookup with three parameters this is close to adequate, but with no output schema the description should at least sketch the shape of a result (service key, name, score, category) so the agent knows what it gets back. Empty-result and invalid-key behavior are also unaddressed.

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 67%, in the mid band, so the schema carries most of the load: 'key' and 'korean_ui_only' are documented inline, and 'limit' is self-explanatory via default/maximum. The description adds only the implicit 'Up to 5 results' ceiling and says nothing about what korean_ui_only filters on or that limit maxes at 5 — a 3 baseline is appropriate.

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 names a specific verb and resource ('Find alternatives to an AI service') and scopes it to 'within the same category', which distinguishes it from search_ai_services and compare_category in practice. It stops short of naming any sibling explicitly, so an agent must infer the boundary rather than read it.

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 only implied: the schema's 'Service key from search results' hints at a search-then-find-alternatives workflow, and the category scoping suggests when this beats a broad search. There is no explicit 'use this when…' or 'do not use for…' statement, and compare_category is never mentioned as the contrasting option.

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