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

Annotations already declare readOnly/idempotent/non-destructive, so credit here comes from the added context: the recompute cadence (once daily after US close), the precise staleness condition (ETF data more than two business days old), and the notable constraint that the LLM rationale may only downgrade the computed signal, never upgrade it. That last detail is non-obvious and materially affects how an agent should trust 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?

Two dense sentences, both front-loaded: the first establishes what the signal is and what feeds it, the second enumerates return contents and operational caveats before closing with the disclaimer. No filler and no repetition of the name/title.

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 the burden of describing returns, and it does: signal, total score, per-component score and reason, raw inputs, rationale, tracked funds, and recent filings. Combined with the cadence and staleness rule, an agent has everything needed to call it and interpret the result.

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 the description could add at the parameter level; the baseline for a 0-param tool applies. Nothing in the description misleads about inputs.

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 concrete artifact (the current ZEC ETF flows indicator) and states exactly what it produces: a daily BUY/HOLD/SELL signal from a named set of inputs. The word 'current' plus the 'daily' recompute cadence implicitly separates this snapshot from the historical sibling get_zec_etf_history, and no other sibling could be confused with it.

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?

The reader can infer this is a once-a-day snapshot rather than a query interface, and 'Informational only, not investment advice' sets a boundary. But it never says when to call this versus get_zec_etf_history, nor does it state that there are no parameters or filters — the selection guidance is implied rather than stated.

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