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

No annotations exist, so the description carries the full behavioral burden and discharges it: it discloses delta-only semantics, the returned fields, cursor stability across restarts, one-time bootstrap, and the $0.015 x402 cost. Pricing and cursor-lifecycle facts are exactly the context an agent cannot infer from the schema.

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 and informative, but redundant: "materially-moved markets in the segment changed since your cursor" is restated as "materially-moved markets... added or changed after it", and the trailing HTTP/pricing block duplicates the cost already stated in prose. The garbled opening token "(delt." further mars an otherwise clear sentence.

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 and no annotations, yet the description still covers return fields, cursor lifecycle, bootstrap behavior, cost, and the free alternative. An agent has everything needed to call it correctly on both the first and subsequent invocations.

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 50% (since is documented inline, category is enum-only). The description compensates for since by explaining it is an opaque cursor sourced from next_cursor and that omitting it bootstraps at now. It adds real meaning beyond the schema, though category semantics remain undocumented.

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 keyset delta over /v1/board/:category returning only materially-moved markets added or changed since a cursor. It also names the payload (changed_count, next_cursor) and the free sibling /changes, so it is clearly distinguishable from probability_board_changes and its per-category relatives.

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 explicit when/when-not and an alternative: "Poll the free sibling /v1/board/:category/changes for counts and pay only when there is something to fetch", plus the bootstrap rule "Omit since once to bootstrap". An agent knows exactly when to call this paid tool versus the free one.

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