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

Annotations already declare readOnly/openWorld/non-destructive, so the safety profile is covered. The description goes further with genuinely useful behavioral context the annotations lack: a $0.02 USDC on Base cost, the plan-key alternative for payment, and the important caveat that 'a measured record describes past calls, not future ones.' Rate limits and refresh cadence are not stated, keeping this short of a 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?

Front-loaded with what the stream is, followed by the filter criterion, payload, caveat, and cost. It is dense with jargon ('caller-rules-2', '95% Wilson lower bound') but every clause carries information; only mild tightening 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 accepts the burden of describing returns and does so ('Each item carries the caller's full measured record ... + the token's deployer score and FDV'). Cost and payment path are also covered. Pagination beyond the simple cursor, and any rate/cadence expectations, are the remaining gaps.

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 the schema already documents limit, since, min_early_rate, and min_rank_score. The description reinforces the rank_score/Wilson-lower-bound semantics and the 0.3 default but adds no syntax, formatting, or interaction detail beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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+resource: a pollable stream of fresh Robinhood Chain calls, filtered to X accounts with a measured early-call record. The filtering criterion (rank_score >= 0.3 / grade B) and the item payload are concrete. It does not name which sibling (e.g. robinx_feed, robinx_caller_calls) it should replace, so the differentiation is implicit rather than explicit.

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?

Usage is implied by the filter semantics, and 'Pollable' plus the cursor wording suggest a continuous-polling pattern, but there is no explicit when-to-use / when-not-to-use guidance and no alternative tool is named. An agent must infer that this is the filtered 'signals' view versus the broader feed/caller tools.

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