get_mmr_history_by_name

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

With no annotations provided, the description carries the burden of behavioral disclosure. It explains the return content (MMR history with match IDs, maps, rank changes, dates) and mentions size limits (max 20), but does not explicitly confirm read-only behavior, auth requirements, rate limits, or error handling. The description is adequate but not deeply transparent about side effects or constraints.

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 well-structured with an opening sentence, a usage note, clearly labeled Args, and Returns. It is slightly verbose with the exclamatory 'Essential for competitive analysis' line, but every other sentence adds value. The front-loaded core sentence allows quick understanding without excessive length.

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 the description is not required to detail return values, yet it still summarizes the key return fields. All four parameters are described, required fields are clear, and the tool is simple. It could benefit from mentioning error behaviors or prerequisites, but for a read-only history getter, the context is reasonably complete.

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 0%, so the description fully compensates by explaining each parameter: name and tag are player identifiers, region lists valid codes, and size includes default and max. This adds significant meaning beyond the raw schema, especially the region enum values and size constraints, though the tag format (e.g., case sensitivity) is not detailed.

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 description clearly states the tool 'Get MMR history with match IDs and maps' with a specific verb and resource. It distinguishes itself from sibling tools like get_mmr_details_by_name (which likely provides current MMR) by focusing on historical data with match IDs. The phrase 'Essential for competitive analysis' adds context without vagueness.

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 implies usage for competitive analysis and specifies the tool retrieves MMR history, but it does not explicitly state when to use this versus sibling tools like get_mmr_details_by_name or get_match_history_by_name. There are no exclusions or alternative tool recommendations, making the guidance implicit rather than explicit.

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