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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds genuinely new behavior beyond them: it re-truncates if the section is still too long, and it discloses an auth requirement ('Needs a free SnoopScan key'), which no annotation conveys.

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?

Front-loaded with the core action, three short sentences, no filler. The trailing auth note is a slightly dangling fragment rather than integrated prose, but it still earns its place.

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?

An output schema exists, so return values need not be spelled out, and the description still covers the key return behavior (next section, possibly truncated again). The only real gap is the undocumented maxChars parameter and lack of explicit sibling routing.

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 0%, so the description must carry the parameter burden. It explains where the required token comes from (a truncation marker), but says nothing about maxChars or its 20000 default, leaving half the parameters undocumented in both places.

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 action (read the remainder of a truncated page) and the continuation semantics clearly enough that an agent can tell this is not scrape/crawl but a pagination follow-up. It does not explicitly contrast itself with any sibling tool, so it falls short of a 5.

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 implies the trigger condition — you call this after a page was truncated and you hold a truncation-marker token — which is useful implied usage. However it never states when not to use it or which sibling to prefer when starting a fresh read, leaving routing to inference.

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