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

Annotations already establish read-only/idempotent/low-risk, and the description adds real context beyond them: the page is bounded, it echoes contextRevision and nextOffset, and excerpt exhaustion must not be over-interpreted. It omits auth requirements, rate limits, and return shape, so not a 5.

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?

Four tight sentences, front-loaded with the core action and immediately followed by the scoping caveats. No filler, though the caveat sentences are dense and could be split by concern.

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?

There is no output schema and the input carries a nested object plus pattern-constrained marker/offset, yet the description covers the semantic cautions and the echo behavior while leaving pagination mechanics (how marker/offset/limit interlock) undocumented. Adequate for the safety story, thin for correct invocation.

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 only 20% and the description does not compensate: it never explains 'marker' (S-prefixed pattern), 'offset' semantics, or the 'limit' bounds/default. Its mention of contextRevision is a return-echo instruction, not an explanation of what that nested parameter means.

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?

States a specific verb+resource+scope ('Read the next bounded page of a frozen source excerpt') and explicitly negates the nearest sibling concept ('NOT full-original pagination'), which cleanly separates it from read_original_page / read_source_original in the sibling list.

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?

Gives clear when-not guidance ('not proof that every original page was read') and a workflow rule ('report partial/missing coverage as a blocker; do not turn exhaustion into full analysis'). It never names the alternative tool to use for full-original pagination, so it stops short of a 5.

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