publish_photo

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

With no annotations provided, the description carries the full burden. It explicitly states 'THIS IS A WRITE OPERATION' and notes the requirement for public URLs. It also mentions the return (post ID and permalink). However, it does not disclose rate limits, destructive behavior, or permission requirements.

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?

Three sentences: first states the action, second gives the critical constraint, third describes the return. Front-loaded, no fluff, every sentence earns its place.

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 2 parameters (1 required), an output schema, and the description covering key behavioral traits and output, the description is complete. It leaves no critical gaps for an agent to select and invoke the tool correctly.

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 coverage is 100% (both parameters have descriptions). The description adds value by specifying that image_url must be a public HTTPS URL (JPEG, <8MB, without auth) and that caption can include up to 30 hashtags (schema only gives maxLength). This goes beyond the 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?

The description explicitly states 'Publish a single photo to the Instagram feed,' providing a specific verb+resource. It is distinct from siblings like publish_carousel and publish_reel, which publish multiple photos or videos.

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 gives clear guidance: the image URL must be publicly accessible, local file paths won't work, and users should upload to S3/Cloudinary/imgur first. It implies this is for single photos, distinguishing from carousel/reel siblings, but does not explicitly state when not to use it.

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