ZeroGEX — SPX/SPY/QQQ/NDX dealer positioning

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

Annotations already declare readOnly/idempotent/openWorld, but the description adds substantial beyond them: free delayed data at least 15 minutes stale, the response self-reports its age and that age must be quoted, and null means 'unsupported by the modeled book' rather than zero. These are exactly the behavioral caveats an agent could otherwise get wrong.

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?

Front-loaded with what the tool returns, then usage triggers, then data-freshness caveat, then the null rule. Dense but every sentence carries load; nothing is redundant padding.

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 compensates by naming every returned level field and defining the null case explicitly. An agent has everything needed to interpret results and quote freshness correctly.

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% and the single enum parameter is already documented opaquely in the schema (ES/NQ projection caveat). The description adds no further param-level meaning, so the baseline of 3 for high schema coverage applies.

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+resource ('modeled options dealer-positioning levels for one underlying') and enumerates the exact levels returned (gamma flip, call wall, put wall, max pain, pin strike, net dealer gamma). An agent knows precisely what comes back. It does not explicitly contrast itself with sibling get_market_gamma_overview, so it falls short of full sibling differentiation.

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?

Gives concrete triggering questions ('where is the gamma flip', 'where are the walls', 'is SPX in positive gamma') and clear when-not guidance (not a price feed, not a forecast, not a trade recommendation, never call live). Strong context, but it never names the sibling alternative or states the condition that would route an agent to get_market_gamma_overview.

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

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context: it returns delayed data (15-minute delay), is free, and omits certain details (walls, max pain, pin strike) compared to the sibling. It also notes the same caveats apply, which is helpful context for the agent.

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 compact and front-loaded. The first sentence states the core purpose and scope. The second sentence gives usage context. The third sentence routes to the sibling. Every sentence earns its place with no redundancy or filler.

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 parameterless read-only tool with rich annotations, the description is complete. It covers what the tool does, when to use it, what it omits, and how it differs from the sibling. No output schema exists, but the description lists the output fields (spot, modeled regime, gamma flip), so the agent knows what to expect.

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 is trivially complete (100% coverage). The description adds meaning by explaining what the tool returns and its scope, which is the only semantic content needed for a parameterless tool. The baseline for 0 params is 4, and the description fully compensates.

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's purpose: a one-line dealer-positioning summary for all six covered underlyings in a single call. It specifies the exact resource (SPX, SPY, QQQ, NDX, ES, NQ) and the specific outputs (spot, modeled regime, gamma flip). It also distinguishes itself from the sibling tool get_gamma_levels by noting it omits walls, max pain, and pin strike.

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 states when to use this tool: for broad openers like 'what does dealer positioning look like today' or 'which indices are in negative gamma'. It also explicitly states when not to use it: when the question is about one symbol, call get_gamma_levels instead. This is clear routing guidance with no ambiguity.

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