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

With no annotations, the description carries the full burden and discloses key behaviors: ~5-second update interval and the distinction between real-time and previous-day data. It doesn't mention return fields or errors, but for a simple read-only quote tool, this is adequate context.

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?

The description is exactly two sentences, front-loaded with the main purpose, and each sentence contributes distinct value: the first states function and update frequency, the second covers data source comparison and parameter guidance. No fluff.

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 tool with only 2 parameters and no output schema, the description covers purpose, usage context, and parameter rules. It doesn't describe the response format, which is a minor omission but not critical for a quote-fetching tool with clear intent.

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 descriptions already cover both parameters at 100%. The description adds practical semantics beyond the schema by specifying that market should be 'tse' for ETFs and listed stocks, and 'otc' for OTC, enriching the enum's meaning.

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 clearly states it obtains real-time intraday quotes with a ~5-second refresh, explicitly distinguishing from OpenAPI's previous-day data. This is unique among sibling tools, which focus on dataset access, not live quotes.

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 explicit when-to-use guidance: use this tool when you need current prices, since OpenAPI only has prior trading day data. It also provides concrete market-selection rules for ETFs/listed stocks (tse) vs OTC (otc), covering the main usage decision.

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