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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds non-obvious result semantics beyond that: sources 'remain separate,' it does not pick a winning price, and it does not backfill missing history — useful expectations for an agent consuming the output.

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 tight sentences with the trigger condition front-loaded, followed by the return summary and the exclusion. No filler, though the phrasing is dense and could be slightly easier to scan.

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 supplies the return shape (series identities, candle intervals), and pagination mechanics are already documented in the cursor/limit parameter descriptions. Annotations cover the safety profile, so nothing essential for correct invocation 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 coverage is only 40% — asset_id, date_from and date_to carry regex patterns but no descriptions. The description partially compensates by tying inputs to 'an exact asset and UTC period,' but it adds no detail on the date format, range semantics, or required-ness beyond what the schema already enforces.

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 a concrete resource and output: it 'Returns series identities and available candle intervals' for a given asset and UTC period. That is more specific than the name alone, but it never names a sibling (e.g. get_market_history) to distinguish this listing tool from the market-history retrievers.

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 when: 'Use when choosing the stored price source for an exact asset and UTC period before comparing posts with prices,' plus a when-not: it 'does not select a winning price or fetch missing history.' It stops short of naming an alternative tool to use instead, so it is context without explicit routing.

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