get_index

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the description does not need to restate safety. The description adds valuable behavior: without a period it returns the current value, with a period it returns daily closes, and MCFTR is marked as total return. No contradictions with annotations.

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, front-loaded with the core result, and the usage note adds direct value without any filler. 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?

Given the output schema exists and annotations are rich, the description is sufficiently complete for correct invocation: it covers the main output, the period-dependent behavior, and a concrete use case. It does not mention pagination, but the schema documents the cursor parameter, so no critical gap remains.

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 description coverage is 100%, so the parameters are already fully documented. The description adds a general behavior link (period triggers daily history) but gives no per-parameter detail beyond the schema. This matches the baseline of 3.

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 the tool returns the Moscow Exchange index value now and, if a period is provided, daily closing history. It also names the intended use case (comparing a security/portfolio return to IMOEX/MCFTR), making the resource and outputs unambiguous. It does not explicitly contrast with sibling tools like get_candles or get_quote, but the index-specific scope is largely sufficient.

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 explicitly says to use this tool for comparing the yield of a security or portfolio against the market (IMOEX, MCFTR), giving clear context for when it is appropriate. It does not name alternatives or state when not to use it, so it stops short of full when/when-not guidance.

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