getSingleImagePostFields

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true. The description adds critical behavioral context: the silent-fallback scenario, the exact structure of the returned array, field properties, and the important detail about whitespace in CSV splits. No contradictions with 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?

The description is relatively long but well-structured with bold section headings. Each sentence adds useful information: purpose, usage, return format, fallback warning, and specific field details. No superfluous content, though slightly verbose in the fallback explanation.

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 lack of an output schema, the description fully explains the return format (bare array, field keys like key, label, required, type, choices) and handles edge cases (fallback, whitespace in choices). It also references sibling tool listPostTypes for validation. No gaps remain.

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 input schema has 100% coverage with a single parameter 'form_name' described as 'Form slug for the post type.' The description adds examples (e.g., 'blog_article_fields, events_fields') and emphasizes that it is required. This adds value beyond the schema, though the schema description was already clear.

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 starts with a clear verb+resource ('Get post field definitions') and immediately specifies what it returns: 'Returns custom fields for a specific post type form.' This distinguishes it from sibling tools like getFormField or getPostTypeCustomFields.

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 states when to use: 'Use when: discovering the per-post-type custom fields before building a create/update payload.' It also provides prerequisites: 'Pass form_name of the target post type' and 'Always verify form_name exists first via listPostTypes.' The fallback warning tells when not to rely on the result. No alternatives are named, but the context is sufficiently scoped.

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