reading_stats

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

The description discloses that results are capped at 50 and that current_progression is always the latest position, which is useful behavioral detail. Since no annotations exist to convey safety or mutation hints, this is helpful but not exhaustive; for example, it doesn't state whether it is read-only, but the tool name implies a read operation.

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 concise and front-loaded with the main purpose, followed by parameter and output details in two paragraphs. Every sentence adds value, with no fluff, though the formatting with blank lines could be slightly tighter.

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 a simple single-parameter tool and an output schema present, the description covers the essential usage details: range format, output structure, ordering, and cap. It is sufficient for an agent to call it correctly, though it could mention the default value explicitly, which is already in the 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 has 0% description coverage, so the description must compensate. It does partially: it explains that range is a number of days like '7d' or 'all'. However, it doesn't specify the full default behavior (default is '30d') or the exact format beyond examples, leaving some ambiguity.

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 provides reading totals, streak, pace, and per-work rows over a span. It does not explicitly differentiate from siblings like list_books or list_highlights, but the resource (reading statistics) is distinct enough that a capable agent can infer its purpose.

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?

It describes the range parameter format and what the results include (per-work rows ordered by time read, capped at 50), which gives clear context for when to use it. However, it doesn't explicitly mention alternatives or when not to use this tool, so it's slightly short of an explicit routing guide.

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