Market overview

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds the source (Yahoo Finance) and the snapshot nature, which is useful context. It doesn't disclose staleness, update frequency, or whether values are delayed, but with annotations carrying the safety burden, a 3 is appropriate.

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 waste. The instrument list is front-loaded, the data fields are specified, and the source is given. Every sentence earns its place.

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 zero-parameter read-only snapshot tool with an output schema present, the description is nearly complete. It states the instruments, fields, and source. The only minor gap is not describing update frequency or data delay, but the output schema likely covers return structure, and annotations cover safety.

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 has zero parameters, so the schema provides no parameter semantics. The description compensates by specifying exactly what data is returned (instruments and fields), which is the only semantic content an agent needs. Baseline 4 for zero-parameter tools is correct.

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 names a specific resource (market overview) and enumerates exactly which instruments are included (BIST 100/30, bank index, USD/TRY, EUR/TRY, gold, Brent, S&P 500, DAX, VIX) plus the data fields (last, change %, 52-week range). This is a clear, specific verb+resource statement that distinguishes it from sibling tools like get_quote or get_price_history.

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 description implies a snapshot/overview use case and the source (Yahoo Finance) is stated. It doesn't explicitly say when to use this over get_quote or get_price_history, but the zero-parameter snapshot nature and the explicit instrument list make the context clear enough for an agent to select it appropriately.

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