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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, and the description adds real behavior beyond them: the widget reuses the captured source numbers and selection rather than recomputing, expired evidence forces a fresh read, and retired regimes and pattern events are deliberately not exposed. This tells the agent both what the widget does and what it will refuse to show.

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 action and its precondition, and every sentence carries routing or behavioral information. The cluster of negations ("not a data fetch, calculation, navigation hub or replacement...") is slightly sprawling but each negation heads off a plausible misselection.

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 one-parameter, read-only widget with an output schema and full annotation coverage, the description supplies the prerequisite, the scope limits, the staleness rule, and the intended non-use cases. Nothing an agent needs in order to call it correctly 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 100% and the single parameter is fully documented, so the baseline is 3; the description adds genuine meaning by stressing that the call reuses captured values and that chart numbers must not be supplied. It does not add format details for evidence_id (the 64-hex pattern lives only in the schema), which keeps it from a 5.

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?

Names a specific verb and artifact (display a focused technical study widget) and narrows the scope to one requested candle-calculated indicator with exact identity/interval/period, or an explicitly native indicator. This distinguishes it clearly from data-returning siblings like research_read_series and from other show_* widgets such as research_show_price or research_show_news.

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?

States the prerequisite ("after evidence from research_read_series is available"), the selection condition ("Use only when a visual helps answer the question"), and explicit exclusions ("Not a data fetch, calculation, navigation hub or replacement for the assistant's interpretation"). It also names the recovery path for stale state: expired evidence requires an explicit new read.

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