Post a photo

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

Annotations provide openWorldHint=true and destructiveHint=false, so the bar is lower. The description adds meaningful behavioral context: the action is 'Publish' (visibility implications), it accepts public URLs only, and it supports draft/scheduling behavior. This goes beyond the annotation-provided safety profile. It does not cover auth or irreversibility, but that is not a critical gap given 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 and resource, followed by a concise reference to sibling behavior. Every word earns its place; there is no filler or repetition of schema details.

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?

For a simple create/publish tool with no output schema and no nested objects, the description plus schema and annotations are sufficient to select and invoke the tool correctly. The only minor gap is that the return shape is not described, but that is optional given the tool's simplicity and the absence of an output schema.

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 60%, with 'url' and 'page' and 'publish_at' already described in the schema. The description compensates for undocumented parameters by mentioning 'optional caption' (caption) and 'Same scheduling and draft options as a text post' (draft, publish_at), adding meaning beyond the bare property names.

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 uses a specific verb ('Publish'), names the resource ('a photo'), and specifies the source ('from a public URL'). It distinguishes this tool from the sibling 'create_post' by explicitly framing it as a photo post variant and referencing 'a text post' for behavioral comparison.

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 clearly implies this tool is for publishing photo posts, and the phrase 'Same scheduling and draft options as a text post' provides contextual comparison to the text-post sibling. However, it stops short of explicitly stating when to use this tool versus 'create_post' or other alternatives, so the guidance is inferred rather than explicit.

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