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

With no annotations, the description carries the full burden, and it does disclose two real traits — the call is free and capped at 3 hits. It says nothing about whether the keyword must be Japanese, how matching works, rate limits, or what a hit contains (snippet vs. ID for speech_text).

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?

One short sentence with the cost signal and the result cap front-loaded; nothing is padded and nothing repeats the tool name.

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?

The tool is simple (one required param, no output schema), but the definition leaves the agent guessing about keyword language/format and about what a 'hit' is, which matters given siblings speech_text and speech_search_pro. Adequate but with clear gaps.

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% and the single parameter has no description in the schema. The description only tells us the parameter is a 'keyword', without language, quoting, or matching semantics — minimal compensation for a completely undocumented parameter.

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 National Diet speeches') plus the result shape ('top 3 hits'), so the agent knows exactly what it does. It stops short of naming speech_search_pro as the alternative, though 'FREE' and 'top 3 hits' faintly imply the limited variant.

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: 'FREE' and 'top 3 hits' suggest a cheap trial lookup versus the sibling speech_search_pro, but no explicit when-to-use or when-not-to-use statement is given. The agent must infer the routing between the three siblings.

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