Advanced: last session receipt

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

Annotations already establish readOnlyHint=true, so the description is not burdened with safety disclosure. It adds useful context about the advanced/internal nature and the raw-session scope, but does not explain what a receipt contains or what 'the chain' refers to. This is adequate but not rich.

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 two short sentences with no filler. The advanced/internal label, the action, and the routing preference are all front-loaded, and every clause adds value.

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 read-only tool with one parameter, the description gives enough to identify the tool and basic invocation intent. However, with no output schema and no explanation of receipt contents or the 'chain' concept, an agent may lack sufficient context to interpret the result correctly.

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 describes session_id only as a required string, and the description provides zero additional parameter guidance. Because schema description coverage is 0%, the description needed to compensate but did not explain the expected format or meaning of session_id in the context of a raw session.

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 action ('Read the last receipt') and a specific resource ('a raw session'), making the core purpose clear. It also frames the tool as advanced/internal, which helps distinguish it from product-facing display tools, although it does not explicitly differentiate from the sibling runtime_session_receipts.

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 instruction to prefer product output (display) unless the user asked for 'the chain' provides a concrete when-to-use guideline. It does not name alternatives explicitly, but the directive is actionable enough for an agent deciding between this and a display-oriented tool.

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