Longhand

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behavioral traits: the chronological nature of the timeline, session ID prefix matching capability, pagination behavior via 'offset', and the 'tail' parameter's specific use case. However, it doesn't mention rate limits, authentication requirements, or error conditions.

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 efficiently structured with zero wasted sentences. It front-loads the core purpose, then explains key parameters with their use cases, and ends with an important exclusion guideline. Every sentence adds distinct value and the entire description is appropriately sized for an 8-parameter tool.

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 tool's complexity (8 parameters, no output schema, no annotations), the description provides substantial context about behavior, usage, and parameter semantics. It covers the main use cases and important distinctions from sibling tools. The main gap is the lack of information about return format or error handling, which would be helpful given the absence of an output schema.

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?

The schema description coverage is 75%, so the description adds meaningful context beyond the schema. It explains the purpose of 'tail' ('great for checking how a session ended') and 'offset' ('paginate through long sessions'), and clarifies that session_id supports prefix matching. This provides valuable semantic understanding that complements the schema's technical documentation.

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 clearly states the tool's purpose with specific verbs ('get a chronological timeline of events in a session') and distinguishes it from sibling tools by explicitly contrasting with 'search_in_context' for searching purposes. It identifies the resource (session events) and scope (chronological timeline).

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 description provides explicit guidance on when to use this tool (for chronological timeline viewing with pagination) and when not to use it ('NOT for searching'), with a clear alternative named ('search_in_context'). It also offers specific use cases for parameters like 'tail' for checking session endings.

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