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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds meaningful context beyond that by stating 'Free; does not use the daily quota,' which is a behavioral cost guarantee not present in the annotations. It also previews what the returned guide covers.

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 sentences with zero filler. The critical 'Start here' call to action is front-loaded, followed by a compact list of guide contents and a useful quota note. Every sentence 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?

For a zero-required-parameter, read-only guide tool with a fully covered schema, the description is complete. It tells the agent what the guide contains, that it is free, and that it should be the starting point. No output schema exists, but the return value is a guide whose contents are itemized, so no critical information 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 description coverage is 100%, and the single 'topic' parameter is fully documented in the schema with an enum and per-value explanation. The description does not add any parameter-level detail, but the schema already carries the full semantic load, so baseline 3 is appropriate.

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 states a specific verb ('Returns') and resource ('the candle market-memory guide') and enumerates concrete contents (evidence, chart presets, call order, band reading, track records, access). It also positions itself as the entry point with 'Start here,' which clearly distinguishes it from the sibling tools that each focus on a specific candle function.

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?

'Start here' gives a clear contextual cue that this should be the first tool an agent invokes before the more specific siblings. It does not explicitly name alternatives or state when not to use it, but the entry-point framing and mention of 'recommended call order' provide sufficient usage direction.

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