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

Annotations already establish read-only, idempotent, non-destructive, and non-open-world behavior, and the description adds real context beyond them: the call is published and identical for every reader, refreshed nightly, and includes historical call performance. It also imposes an output obligation — surface the not-advice line and run date — which an agent would otherwise miss.

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 sentences, front-loaded with the resource and its contents followed by usage and display requirements. The content enumeration in the first sentence overlaps with the existing output schema, which costs some efficiency, but no sentence is 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?

With a full output schema present, the description needn't explain return values, and annotations cover the safety profile; what the description supplies (data freshness, coverage scope, mandatory disclaimer) is the right complement. It leaves minor gaps on behavior for unknown or ambiguous symbols and non-US tickers.

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 single parameter is already fully documented in the schema with symbol and company-name examples, so the baseline is 3. The description adds the US-only scope constraint and reinforces that either a symbol or a company name is accepted, which is meaningful disambiguation for a one-param lookup.

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 (StockMap's published call on one US stock) and enumerates exactly what the answer contains: the 14-day call, reasons for/against, past-call record, price and day's change, and what changed. It is clearly distinguishable from siblings like compare_stocks, sector, and last_night, which operate on other scopes.

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?

Explicitly says when to use it: someone asking how a US stock looks, whether it reads strong or weak now, or what the model's call is — including when StockMap isn't named. It gives no exclusions or named alternatives (e.g., when to prefer compare_stocks or sector), so it stops short of full routing guidance.

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