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

Annotations already cover read-only, idempotent, closed-world safety profile, so the description is not required to restate them. It does add real behavioral context: as-filed data with no estimates, no API key needed, and limited coverage that is growing daily, which tells the agent about data freshness and scope limits.

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 the source and data type, then a compact field list, args, and access constraints. The field enumeration is dense but earns its place since there is no output schema; only minor trimming is possible.

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 listing the returned metrics and disclosing source, coverage, cost, and auth requirements. An agent has everything needed to invoke it 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 ticker parameter is already documented with an example in the schema. The description repeats the ticker example with no added syntax or format guidance, so baseline 3 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 and resource (company fundamentals) plus the exact source (SEC EDGAR XBRL company facts, as-filed), and enumerates the returned metrics (revenue, net income, diluted EPS, margins, YoY growth). This is clearly separable from siblings like get_earnings_history or get_macro_snapshot without opening a schema.

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 gives useful context ('free public data, no key', large-cap US filer coverage) but never states when to prefer this over alternatives such as get_earnings_history or get_price. Usage is implied rather than routed explicitly.

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