Add Picklist Values to Existing Field

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

Annotations already communicate readOnly=false, destructive=false, and idempotentHint=true. The description adds a critical behavioral trait: 'without removing existing values', which directly addresses what is preserved (i.e., nothing existing is destroyed). This adds value beyond the annotations and clarifies the operation's non-destructive nature.

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 short sentences, front-loaded with the action. The first sentence states the purpose and key constraint; the second provides the use case. Every word earns its place with 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 tool has only 2 parameters with rich schema descriptions and an open-world annotation. No output schema exists, but the description adequately covers the operation scope and expected outcome. It does not mention error handling or permissions, but for an additive, non-destructive operation this seems sufficient. Minor gap: no mention that adding a duplicate value might fail, but not critical.

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%; all parameters (objectFieldFullName and values) have detailed descriptions in the schema, including the nested value properties (label, fullName, color, etc.). The tool description itself adds no extra parameter information, so 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?

Description uses a specific verb ('Adds') and identifies the resource ('new picklist values to an existing Picklist or MultiselectPicklist field') with a key differentiator: 'without removing existing values'. This distinguishes it from potential update/replace operations and from sibling tools like sf_create_custom_field.

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?

Provides explicit when-to-use guidance: 'Use when a user wants to add new options to a dropdown.' It does not name alternatives (e.g., for replacing values) but the 'without removing existing values' clause clarifies it is not for editing. This is clear context, though not an explicit exclusion list.

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