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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds useful behavioral context: it uses the official MLB Stats API, automatically resolves batter/pitcher names, and returns season-split hitting lines with career totals. This goes beyond the structured annotations, though it omits potential error or rate-limit behavior.

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?

The description is compact and front-loaded, using one dense paragraph to cover purpose, input formats, examples, output metrics, and seasonal splitting. No filler or redundant restatement of the tool name.

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?

For a simple three-parameter tool with no output schema, this description is complete: it explains accepted inputs, automatic name resolution, optional season limiting, and the specific returned hitting statistics. An agent has enough context to call it correctly without requiring additional documentation.

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 100%, so parameters are already documented. The description adds meaningful extras: both batter and pitcher accept names or numeric IDs, names are resolved automatically, and 'season' is optional and controls career-wide versus single-season results. This supplements the schema with practical semantics.

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 opening phrase 'MLB BATTER-vs-PITCHER history' states a specific verb-like purpose with a clear resource and scope. Concrete examples like 'how has Yordan Alvarez hit against Tanner Bibee' make it instantly distinguishable from the other MLB sibling tools such as mlb_player_stats or mlb_boxscore.

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?

The description gives clear context and concrete input examples, making it obvious when to call this tool for batter-versus-pitcher matchups. It does not explicitly name alternatives or state when not to use it, but the purpose is specific enough that an agent can infer appropriate usage.

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