Read matching LINE chat activity

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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful behavioral context beyond that, including that the operation is consistent ('one consistent operation') and that it returns explicit chat- and message-level completeness metadata. No contradictions with annotations.

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?

Three tight sentences: core behavior, return metadata, and an example use case. No filler or redundant restatement of schema fields. The most important operational detail (name substring + bounded time window) is front-loaded.

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 a rich output schema, comprehensive annotations, and 100% schema description coverage, the description provides the remaining operational and use-case context. Nothing needed to correctly call the tool 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 all six parameters are already documented in the schema. The description adds 'literal substring' and 'bounded time window' phrasing, but these largely restate schema semantics rather than introducing new parameter-level meaning. Baseline 3 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 states a specific verb+resource: resolving chats by name substring and reading a bounded time window from them. It clearly differentiates from siblings like list_chats, get_messages, and get_recent_activity by emphasizing the combination of chat filtering and time-bounded message retrieval.

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?

Provides a concrete example of when to use the tool ('reading today's messages across all chats for one customer or project'), which gives clear context. It doesn't explicitly state exclusions or name alternatives, but the use case makes the intended scope easy to infer.

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