gex_heatmap

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

There are no annotations, so the description carries the full burden. It discloses IP rate-limiting, caching for ~5 minutes, that no key is needed, and that symbols outside the watchlist return an error. This is significant behavioral context that goes beyond typical tool descriptions.

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 well-structured with a clear opening sentence, an Args section, and a Returns section. However, there is minor redundancy: 'no key needed' and 'lightweight, unauthenticated way' convey the same point. It could be slightly tightened without losing clarity.

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 simple tool with two parameters, no output schema, and no annotations, the description is remarkably complete. It covers the purpose, usage guidelines, parameter semantics, error behavior, and return format, making it fully sufficient for an AI agent to select and invoke the tool 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?

The schema provides no parameter descriptions (0% coverage), so the description must compensate. It fully explains `symbol` with examples (SPY, QQQ, AAPL, etc.), the default, and the error case for invalid symbols. For `expiry`, it clarifies it is an optional Unix timestamp and gives practical advice ('omit for the nearest expiry'). This adds substantial meaning beyond the bare schema.

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 it is a 'Public GEX-by-strike heatmap for a watchlist symbol' and explains its purpose as 'a lightweight, unauthenticated way to see gamma exposure per strike.' It distinguishes itself from the sibling tool `get_gex` by noting the watchlist-only scope and the authenticated alternative for arbitrary symbols.

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 specifies when to use this tool: for watchlist symbols, without a key, and without a plan. It provides a direct alternative by saying 'use the authenticated `get_gex` for arbitrary symbols,' which gives clear separation of usage scenarios.

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