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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false). The description adds genuinely useful non-annotation context: the payload size (~1.5 KB), the fact it is a consolidated snapshot, and the exact content sections, including a plain-text variant. No auth, rate-limit, or freshness mechanics are described, but for a no-arg read-only brief the added detail is solid.

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 compact sentences, front-loaded with the 'whole Book in about 1.5 KB' hook, then the content list, then the usage cue. Every clause carries information; the only minor slack is the trailing 'plus a plain-text version'.

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 zero parameters and no output schema, the description must describe the return payload itself, and it does so by enumerating the sections. It is complete enough for an agent to decide to call it, though it could say more about how current the 'freshness' data is.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 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 names the resource precisely ('the whole Book') and enumerates the specific sections returned (freshness/caveats, verdict and lens mix, 30-day movers, health, alerts), which distinguishes it from narrow siblings like tc_moves or tc_alerts. It doesn't explicitly name those siblings as alternatives, but the aggregate-vs-single-topic distinction is inferable.

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?

'Use for market-wide questions' gives one positive usage condition, which is a reasonable routing hint toward this tool over per-token siblings. However, it offers no when-not-to-use guidance and does not name an alternative tool for narrower questions.

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