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

Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true. The description adds context about merge semantics and the clearing behavior for empty strings, which goes beyond the annotations. It does not contradict the annotations.

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, front-loaded with the core action ('Merges the given path/value pairs into a locale's content'), followed by a critical behavior and a requirement. No filler or repetition.

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?

The description, combined with the detailed schema and annotations, covers the essential behavior for calling the tool. It mentions the plan requirement and merge/clearing semantics. The output schema exists, so return values are covered. Minor gap: it doesn't explicitly state that the translation must already exist or what happens on failure, but these are not critical for invocation.

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?

The schema provides 100% coverage, with each parameter described. The description's mention of empty string clearing is redundant with the content parameter's schema description. The description adds no new parameter-level meaning beyond what the schema already provides.

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 verb 'Merges' and the resource 'into a locale's content', which distinguishes it from create_translation, delete_translation, get_translation, and list_translations. It also adds a specific behavioral nuance (empty string clears to source fallback), making the purpose unmistakable.

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 (update an existing translation's content) but does not explicitly state when to use it versus alternatives like create_translation or delete_translation. The plan requirement is mentioned but is a prerequisite, not usage guidance. No exclusions or alternative conditions are given.

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