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

With no annotations provided, the description carries the full burden and meets it: it explicitly states 'Read-only; never rebuilds, never bills' and discloses that include_physical returns very large payloads. This gives the agent strong expectations about side effects, cost, and performance.

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 information-dense but not bloated. Purpose is front-loaded, the workflow constraint follows immediately, and every sentence contributes either usage sequencing, parameter guidance, or behavioral disclosure. No filler or redundant restatement of the schema.

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 3-parameter, no-output-schema tool with no annotations, the description is complete: it explains when to call it, what it returns at a sufficient level, how to reference the document, how to handle the heavy flag, and the read-only/no-cost behavior. Nothing critical for correct invocation 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 coverage is 100%, so the baseline is 3, but the description adds real value beyond the schema: documentRef is 'served free from cache' and the map result is the preferred source, while include_physical is tied to 'raw positioned tokens/vector paths' and a concrete payload-size warning.

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 opens with a precise verb/resource pairing: 'Tier-2 detail for ONE page of an already-mapped datasheet.' It enumerates exactly what the page-level inspection returns — measured anatomy, headings, first lines, and module claims — and distinguishes it from the Tier-1 map, so an agent can immediately tell it apart from sibling tools.

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 gives explicit sequencing: use AFTER extract_document_map, when the Tier-1 index says a page matters and its one-line summary is insufficient. It also provides the prerequisite input (document.sha256 from the map) and warns when the heavy include_physical option should or should not be enabled.

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