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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false. The description adds useful context beyond annotations: EOD nature, coverage of ~2,500 tickers, and the exact price-history fields returned. It stops short of describing latency, pagination, or data freshness, but the read-only safety profile is already covered.

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 no filler. The core purpose is front-loaded, followed immediately by the returned fields and ticker-format rules, all of which are directly relevant to invoking the tool.

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?

No output schema exists, so the description carries the burden of explaining return values. It lists the key returned measures (latest close, changes, 52-week range, last ten sessions) and ticker conventions, making it sufficiently complete for a price-history read. Minor gaps remain around output format, currency handling, and timezone, but the essential calling information is present.

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%, so the single ticker parameter is already documented. The description adds valuable formatting rules beyond the schema: US tickers are bare (NVDA) and foreign tickers require exchange suffixes (005930.KS, 6857.T, ASML.AS).

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?

States a specific verb+resource: 'End-of-day price read' for tickers in Closelooknet's data lake. It enumerates the exact outputs (latest close, close-to-close changes over multiple horizons, 52-week range, last ten sessions), which clearly differentiates it from snapshot or ranking siblings.

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?

Usage is implied by 'End-of-day price read' and the listed outputs, but there is no explicit when-to-use vs alternatives guidance or exclusions. It does not name sibling tools or state when another tool would be more appropriate.

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