get_last_messages

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

With no annotations provided, the description must carry the behavioral disclosure burden. It clearly indicates a read-only operation ('Reads'), but does not disclose return format, ordering, error behavior, or whether messages are marked as read. These are notable gaps for a no-annotation tool.

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 short, purposeful sentences. The core purpose is front-loaded, followed by a crisp usage rule and a critical warning. No wasted words or redundant schema repetition.

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 two-parameter read tool with full schema coverage, the description covers purpose, usage conditions, and a workflow constraint. It lacks an explicit statement about return shape or side effects, but the tool is simple enough that the missing details are minor.

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 100%, so the schema already documents both count and chat_name fully. The description adds no additional parameter-level meaning beyond restating 'specific Teams chat,' so the baseline score of 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?

Description states a specific verb and resource: 'Reads the last N messages from a specific Teams chat.' It also clarifies the plural scope ('multiple recent messages'), which distinguishes it from singular siblings like get_last_message and get_last_unread_message.

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 explicit when-to-use guidance: 'Use this ONLY when the user asks for multiple recent messages or recent conversation history.' It also gives a clear exclusion: 'NEVER call list_teams_chats first.' This strongly steers an agent away from inappropriate alternatives.

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