chat_activity

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

Explicitly declares 'Read-only with no side effects.' Since no annotations are provided, the description adequately covers behavioral transparency. However, it lacks details on sorting or time window for 'recent activity,' which would be beneficial.

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 sentences, each serving a purpose: first conveys functionality, second declares safety, third provides usage guidance. No wasted words.

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?

With one parameter and an output schema, the description covers purpose, behavior, and usage guidance comprehensively. No gaps remain for this complexity level.

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?

Only one parameter (limit) with 100% schema description coverage. The tool description adds no extra meaning beyond the schema's explanation of the limit range and default. Baseline score 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?

Clearly states the tool lists Signal chats ranked by recent activity with specific fields (last message date, last reply date, count of unanswered inbound messages). Differentiates from sibling list_chats by specifying its unique output.

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?

Explicitly states when to use this tool ('identify chats that need a response') and when to use the alternative ('Use list_chats instead for a general chat directory with message previews').

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