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

Annotations already establish readOnly/openWorld/non-destructive, so the description correctly focuses on what annotations can't say: the concrete return fields and the data-source caveat that quotes come from the general CAR feed and broker accounts are not yet used for OHLCV. That caveat is genuinely decision-relevant for an agent reasoning about data reliability.

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?

Three short sentences, front-loaded with purpose then return payload, no filler. The trailing parenthetical about data sources is dense but earns its place; only slight tightening would improve readability.

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?

With no output schema, the description carries the burden of describing returns and does so by listing the field set, plus it discloses the data-source limitation. A minor gap: no mention of latency, streaming vs point-in-time, or nullability of fields like bid/ask for illiquid symbols.

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%, with both symbol and account_id documented in-schema including the cross-reference to get_trading_accounts, so the description need not repeat it. The description adds no parameter-level semantics beyond the schema, which is the expected baseline here.

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 and resource ('Get live market state for a symbol') and enumerates the returned fields (price, bid/ask, volume, volatility, trend), so the agent knows exactly what it gets. It does not name a sibling such as compare_markets or get_market_context to draw the boundary, so it falls short of the 5 bar.

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?

Usage is implied rather than stated: 'live market state' signals this is the current-snapshot tool versus get_historical_context or get_market_context, but no when-to-use or when-not-to-use rule is given. The note about broker accounts is a data-provenance caveat, not routing guidance.

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