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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds genuine behavioral context beyond that: a 30-minute refresh cadence and a worked example of what a movement signal looks like. It does not address pagination or how far back the price history goes.

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, zero waste. The data payload is front-loaded, the usage cue and refresh cadence follow, and the parenthetical example earns its place by disambiguating 'movement'.

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 return-value burden and does so by naming the returned fields. All four params are optional and fully schema-documented, and refresh cadence is disclosed. Missing only a note on history depth / pagination behavior.

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 team, limit, sort_by and include_series fully, including the sort_by default and enum. The description adds no parameter-level syntax or semantics beyond that, so the baseline 3 applies.

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 ('MLB game line movement for today') and enumerates exactly what is returned: opening/current total, moneylines, implied runs, change since open, price history. The concept of movement over time is naturally distinct from a static odds feed, though it never explicitly names sibling invoke_mlb_game_odds to sharpen the boundary.

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?

'Use it to see where the market moved' gives clear when-to-use context, reinforced with a concrete example (total dropping from 9 to 8.5). No exclusions or named alternatives are provided, so it does not reach the top band.

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