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

With no annotations, the description carries the behavioral burden and does disclose meaningful traits: data starts in January 2010, from/to/limit control the window, and there is an alternative mode returning the latest settlement's largest fails by value. It does not spell out output format or the exact trigger for the second mode, but the core behavior is transparent.

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 a single dense sentence that front-loads the resource and data fields, with the parameter behavior in a parenthetical and the second mode stated at the end. It is compact but slightly run-on; splitting into two sentences 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?

There is no output schema, so the description must convey return behavior, and it does list quantity and price by settlement date. However, it leaves ambiguity about when the second mode triggers and what the default behavior is when no symbol or date range is supplied, which is important given all parameters are optional.

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 coverage is 100%, giving baseline 3. The description adds value by explaining that from, to, and limit jointly select the window and that the symbol parameter selects a FTD series, while the alternative mode connects to the optionality of parameters. This goes mildly beyond the schema's per-field descriptions.

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 identifies the resource (SEC fails-to-deliver data), the fields (quantity and price), and the dimension (settlement date), and gives coverage since January 2010. It does not explicitly contrast this with sibling tools such as threshold_list or short_interest, so it stops short of full 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?

The description implies the tool is for retrieving SEC fails-to-deliver records and offers two modes: a date-window query for a symbol and a top-fails-by-value query for the latest settlement. It gives no explicit when-to-use versus alternatives or exclusions, so an agent must infer when this tool is appropriate.

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