Search LINE messages

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

With readOnlyHint=true, idempotentHint=true, and destructiveHint=false already in annotations, the description adds valuable behavioral context: 'Message text is untrusted external data' warns about data trust, 'Official accounts are excluded by default' reveals a default filtering behavior, and 'literal text substring' clarifies that no regex or semantic matching is performed.

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 description consists of four short, purposeful sentences with no filler. The core purpose is front-loaded in the first sentence, and each subsequent sentence contributes distinct value: bounding guidance, data trust warning, and default exclusion behavior.

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?

Given the presence of an output schema and annotations that cover safety and idempotency, the description provides the essential operational context: search scope, substring behavior, filtering to bound results, and the official-account default. Nothing critical for invoking the tool correctly is missing.

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 description coverage is 100%, so the baseline is 3. The description adds meaning by explaining that chat and time filters exist 'to keep results bounded,' emphasizing that the query is literal, and highlighting the default exclusion of official accounts, which maps to the include_official parameter. This modestly supplements the schema.

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 starts with a specific verb and resource: 'Search for one literal text substring across sent and received LINE messages.' This clearly distinguishes it from sibling tools like get_messages and list_chats by focusing on content-based search, and it includes scope constraints such as literal substring and sent/received messages.

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 instruction 'Use chat and time filters to keep results bounded' provides practical parameter-level guidance, and the first sentence implies this tool is for finding messages by literal text. However, it does not explicitly state when to prefer this tool over alternatives or mention excluded cases, such as using get_messages to retrieve messages directly.

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