set_account_slot

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

Annotations already declare destructiveHint=true and idempotentHint=true. The description adds value by stating 'Values are stored as strings,' which signals type coercion, and clarifies the slot is a custom key-value pair. It does not repeat annotation flags, and there is no contradiction.

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 three short paragraphs: purpose, use cases, and parameter breakdown. Every sentence carries necessary information, and the purpose is front-loaded. No redundant or filler text.

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?

Given the 3 required params, output schema presence, and annotations (idempotent+destructive), the description is complete. It covers parameter formats, string coercion, and use cases; the only missing detail is explicit overwrite behavior, which idempotentHint/destructiveHint already imply.

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 has 0% description coverage, so the Args block carries full weight. It explains account ref formats (full path, %short GUID, full 32-char GUID), gives key examples, and notes value is always stored as a string. This fully compensates for the bare schema.

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?

Description opens with 'Set a custom metadata slot on an account,' a specific verb and resource. It further clarifies 'Stores a key-value pair on the account,' distinguishing it from sibling get_account_slots and delete_account_slot. No ambiguity about what is modified.

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?

Explicitly says 'Use for APR, credit limits, reward rates, or any per-account metadata,' giving clear when-to-use context. It does not explicitly name sibling alternatives or provide exclusions, so it falls short of a 5 but is well above implied usage.

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