ListReadingSessions

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered. The description adds useful content semantics (newest-first ordering, session = one timed reading period, multiple sessions per day) but no pagination, auth, or rate-limit behavior beyond what the cursor parameter already documents.

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?

Two sentences, zero filler, and the most decision-relevant facts (what is listed, ordering) are front-loaded before the clarifying definition of a session.

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 rich annotations, a full input schema, and an output schema covering return values, the description needs only to frame ordering and granularity, which it does. Pagination behavior is conveyed by the cursor parameter in the schema, so nothing critical is missing.

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 description coverage is 100%, with limit, since, and cursor each documented in the schema itself. The description adds no parameter interpretation, so the baseline 3 for a fully-documented schema applies.

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 gives a specific verb and resource ('List the user's reading sessions') plus ordering ('newest first') and a precise definition of a session as a timed reading period, which implicitly separates it from aggregate siblings like SummarizeReadingTime. It never names an alternative sibling, so differentiation relies on inference rather than explicit contrast.

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?

There is no when-to-use, when-not-to-use, or alternative-routing guidance; the description only states what the tool returns. An agent must infer from the name alone that this is the right call versus ListRecentHighlights or SummarizeReadingTime.

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