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

Annotations already cover read-only, idempotent, open-world and non-destructive, so the description's added value is the cost disclosure (3 credits) and plan availability (every plan) plus the fact that the response carries consensus open/current price and a book-count confirmation. It stops short of stating freshness/latency or pagination behavior beyond the limit parameter.

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?

One dense sentence stating what is returned, followed by the cost and plan line — no filler, and the core purpose is front-loaded.

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?

An output schema exists, so return format needn't be spelled out, and annotations carry the safety profile. But for a 7-parameter filter tool with under-half schema coverage, the description leaves the numeric filters (min_move_pct, min_books, max_mins_to_jump) and the sibling routing undefined.

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 only 43%: country, direction and categories are documented in the schema, while limit, min_books, min_move_pct and max_mins_to_jump are not. The description implies the concepts behind min_books ('how many books confirm the move') and min_move_pct ('price has moved'), but gives no thresholds, units, or the meaning of the pre-jump time window, so it only partially compensates.

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 (racing runners whose price has moved across several bookmakers, open vs current) and even glosses the betting jargon with 'steam and drift', so an agent can tell it is about price movement rather than raw prices or results. It never names sibling alternatives such as odds_changes or sports_movements, so differentiation from those is left to inference.

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 only implied: an agent can infer you call this to surface firming/drifting runners before the jump. There is no explicit when-to-use, when-not-to-use, or 'for sports use sports_movements instead' routing despite several overlapping siblings.

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