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

Annotations already establish this as a read-only, idempotent, non-destructive tool. The description adds useful context beyond that: the scan universe and timeframes, the ranking basis (neighbour band width vs all-history), the row-to-tool linkage, and an important framing caveat ('A research lead, not a direction or trade signal'). It stops short of describing output shape or latency/cost, but the added context is meaningful.

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?

Four short sentences, front-loaded with the entry-point guidance and the scan scope. The caveat is placed at the end where it belongs, and no sentence is redundant.

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?

There is no output schema, so the description carries return-value burden. It partially addresses this by saying each row links to get_candle_live_pulse and explaining what is ranked. What an agent gets back (fields, row count, ordering details) remains slightly underspecified for a scanner tool, but overall it is complete enough to invoke correctly.

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%, so the schema already documents all four parameters with enums, defaults, and allowed values. The description restates the defaults (BTC, ETH, SOL across 15m/1h/4h) and notes configurability, which is mildly helpful but largely duplicative. 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 and resource: it scans BTC/ETH/SOL across timeframes and ranks where historical twins agree most on move magnitude. It also positions the tool as the entry point ('Start here if you do not know which market to look at'), which cleanly separates it from detail-oriented siblings like inspect_candle_analogue and get_candle_live_pulse.

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 an explicit when-to-use condition ('Start here if you do not know which market to look at') and notes no arguments are required, plus points to get_candle_live_pulse as the follow-up. It does not explicitly say when to skip this tool in favor of other siblings, so it falls just short of full routing guidance.

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