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

Adds substantial context beyond the annotations: subscription/billing prerequisites, the 7-day trial path, the exact failure mode (402 plus card.payUrl), and the authentication mechanism (connection's x-api-key, never as an argument). The annotations only say openWorld/non-idempotent/non-destructive; the description explains the paid, metered nature that matters operationally.

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-loads the action in the first sentence, then layers billing and auth constraints. Five sentences is on the longer side, but each carries a distinct operational fact (sources, subscription, 402 behavior, auth, human-chat separation); only the trial/trial-checkout clause is slightly verbose.

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?

No output schema exists, yet the description does not describe the shape of a successful answer (e.g., prose response, citations, latency). It compensates well on auth and failure paths, but an agent still lacks a picture of what a paid call returns.

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?

Only one parameter and schema description coverage is 100%, with the schema already describing 'question' as a research question about tickers, events, or the operator's book. The description reinforces that it is a single question but adds no constraint, format, or scoping detail beyond the schema. 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 ('Ask the agent Marx Pro desk one research question') and enumerates the data sources used (SEC last-close, reported financials, Marx Key Insights, operator's saved ideas). It also explicitly distinguishes this desk from the human Marx Pro chat, so an agent cannot confuse the two.

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 clear invocation context: one research question, requires this agent's own Agent Marx Pro subscription, and what happens when unpaid (HTTP 402 with card.payUrl). It does not name an alternative tool or state when not to use it, but none of the siblings overlap, so the routing risk is low.

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