Read a chat by chat_id

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

The description goes well beyond the rich annotations by disclosing default/clamping behavior, Unix-second timestamp filtering, opaque cursor pagination, possible truncation with failure conditions, local cache limitations, and a prompt-injection warning that message bodies are user-authored content. This is exceptional behavioral transparency.

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 is information-dense with no fluff. It front-loads the core behavior, then explains parameters, pagination, truncation, cache caveats, and content safety. Every sentence adds practical value, and the length is justified by the tool's complexity.

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 output schema exists, return values need not be described. The description covers ordering, paging, failure modes, data freshness, and security. Only include_deleted remains under-described, but overall the tool definition is highly complete and actionable for an agent.

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?

With schema description coverage at 0%, the description compensates well by explaining limit defaults and clamping, before/after timestamp semantics, and cursor usage. However, include_deleted is not mentioned anywhere, leaving one parameter's meaning to its schema title only.

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 and resource: 'Returns a newest-first window of messages from one chat (by chat_id).' This clearly differentiates it from sibling tools like list_chats and get_chat_metadata by emphasizing single-chat message retrieval rather than a chat list or metadata.

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 intended use case is clear: call this tool when you need a chronological message window for one specific chat. It does not explicitly name alternative tools or exclusion criteria, but the 'from one chat' scope provides enough context to avoid obvious misuse with list_chats or search_messages.

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