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

With readOnlyHint=true already covering the safety profile, the description goes further by disclosing concrete cost ($0.003/call) and the shape of the payload (bias range, drivers, source events with graph path). It omits latency/rate-limit behavior, but adds real context beyond the annotation.

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?

Two sentences, front-loaded with what the tool returns before the usage guidance. Every clause carries information — fields, range, use case, price — with no 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 no output schema, the description carries the burden of explaining return values, and it does so by enumerating the payload fields. Combined with the readOnly annotation, an agent has enough to call it correctly, though precise field formats/typing are left implicit.

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%, so limit, since, and asset_id are already fully documented in the schema. The description reinforces the window concept but adds no syntax or format detail beyond the schema, making the baseline 3 appropriate.

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 states a specific resource and scope (net directional pressure on ONE asset over a window) and enumerates what the result contains: bias (−1..+1), event count, strongest supportive/negative drivers, and source events with rationale and graph path. It is clear what the tool produces, though it does not explicitly distinguish itself from siblings like explain or exposure_graph.

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 concrete when-to-use guidance: before entering or sizing a position, or to explain a move (with a worked example, 'why is MSTR down today?'). There are no explicit exclusions or named alternatives, so it falls short of a 5.

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