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

Annotations already cover readOnly/openWorld/non-destructive, so the bar is lower, and the description adds real operational context: a 2000-ticker ceiling, the fact that a full-size call is still one upstream request, the exchange-prefix requirement, and a not_found list for unrecognized tickers. That goes meaningfully beyond the annotation set, though it omits rate limits or update latency.

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 one-line summary followed by Args and Returns sections; every block carries information. The Args/Returns formatting is slightly heavier than the payload needs, but nothing is wasted.

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, yet the description enumerates the return envelope fields (ticker, symbol, description, exchange, price, open, high, low, currency, change_percent) and the not_found list. Combined with the parameter detail, an agent has everything needed to call and consume 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?

Schema coverage is 0%, so the description carries the full burden and does so well: it specifies comma-separated EXCHANGE:SYMBOL syntax, gives a concrete example, states the 2000 max, and warns that the exchange prefix is mandatory because lookup is exchange-scoped. Essentially nothing about the single parameter is left ambiguous.

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+scope: 'Current price + daily % change for specific stock symbols.' The multi-symbol, exchange-scoped nature distinguishes it somewhat from single-ticker siblings like yahoo_price or price_chart, but those siblings are never named, so the agent must infer the boundary. Clear purpose, no explicit sibling differentiation.

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?

Implies usage via 'specific stock symbols' and the required EXCHANGE:SYMBOL format, which signals this is a direct lookup rather than a scan. However, it never says when to prefer this over yahoo_price, market_snapshot, or price_chart, and offers no exclusions or prerequisites beyond the format.

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