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

Annotations already declare the read-only/idempotent/non-destructive/open-world profile, but the description adds real value beyond them: it enumerates the return payload (WARC headers, captured HTTP headers, page body), notes body truncation via a user-controlled byte cap, and flags that the operation is keyless (no auth). Error/failure behavior and any rate limits are not covered.

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?

Three sentences, front-loaded with verb + resource + mechanism before the usage cue and truncation note. Minor redundancy in 'as it was crawled' but no padding that obscures the core instruction.

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 no output schema, the description correctly carries the burden of describing returns (WARC headers, HTTP headers, body) and truncation, and annotations cover the safety profile. It is complete enough to call correctly, though error/empty-result behavior is not addressed.

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; the description earns above baseline by explaining the provenance of filename/offset/length (they come from a commoncrawl_index_search result) and by tying max_body_bytes to the 'truncated to a byte cap you control' behavior. It adds meaning about where the values originate rather than just restating the schema.

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 (read) plus resource (one archived page / WARC record) and the exact mechanism (byte range with filename, offset, length). It explicitly distinguishes itself from the sibling commoncrawl_index_search by naming it as the source of its inputs, so an agent can tell the two apart without opening either schema.

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 gives a clear workflow condition — pass filename/offset/length from a commoncrawl_index_search result — and a strong use cue ('AUTHORITATIVE for what did this page actually say when it was crawled', including changed or offline pages). No explicit when-not-to-use or named alternative for the archival siblings (archive_compare, archive_evidence), so it stops short of 5.

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