ig_get_current_candle

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

With no annotations provided, the description carries the burden of behavioral disclosure. It openly explains the shared streaming subscription, the non-push snapshot limitation, and the derivation of resolutions from IG streaming candles. It doesn't address authorization or failure modes, but these are less critical for a read-only candle retrieval.

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 concise, front-loaded with the primary purpose, and every sentence adds value—covering resolutions, subscription context, and the polling limitation. No wasted words.

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?

The description is complete for the core use case (getting a forming candle) and the output schema covers return values, so that's not a gap. However, the missing parameter semantics for epic and timezone reduce overall completeness. It's a solid but not fully comprehensive description.

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 schema has 0% coverage, so the description must explain all parameters. It only documents the supported values for resolution and neglects to explain epic or timezone formats/meanings. This is a significant gap given the low schema coverage.

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 gets the latest forming IG chart candle, with a specific verb and resource. It distinguishes itself from sibling tools by explicitly mentioning the shared streaming subscription and derived resolutions, which is unique among the listed tools.

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 provides clear usage context: use for the latest forming candle, and instructs to call again for a newer snapshot due to MCP's non-push nature. It doesn't explicitly name alternatives like ig_get_historical_prices, but the context is sufficient for an informed agent to select this tool for current candle data.

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