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

Annotations already cover the safe/idempotent/read-only profile, and the description adds genuinely new behavior: a paid x402 call at 0.001 USD and a documented failure mode when no real data source is connected. It still omits pagination or response shape, keeping it below 5.

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?

A single compact sentence with the pricing and failure behavior front-loaded and no filler. It is slightly telegraphic, but nothing is wasted.

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 and an undocumented 'limit' parameter, the description should say something about the bar format (granularity, time range, count) to let an agent call it correctly. It covers cost and failure but not the shape or scope of what comes back.

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 only 33% and the description adds nothing about parameters, notably leaving 'limit' undefined in both places. Only payment_signature is documented, and that documentation lives in the schema, not the description.

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 resource (real broker price bars) scoped to one symbol, which is clearly distinct from sibling tools like mnemos_options_scan or mnemos_arb_scan. It does not name a sibling explicitly, so it stops short of 5, but the purpose is immediately understandable.

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 when the call is appropriate by flagging the paid x402 model and that it errors when no real source is wired, which is useful context. However, it never states when to prefer this over a cached or scanning alternative among the siblings, leaving routing to inference.

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