Push Image Message

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

No annotations are provided, so the description must carry the behavioral disclosure burden. It only says 'Send an image' and does not mention side effects, auth requirements, quota consumption, delivery semantics, or error behavior. For a mutating API call, this is a significant gap beyond what the schema covers.

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 a single front-loaded sentence with no filler, repetition, or unnecessary detail. It states the verb, object, and target destinations in the fewest possible words.

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 full schema compensates for missing parameter prose, but there are no annotations and no output schema. The description does not offer usage exclusions, behavioral caveats, or guidance on when to prefer a broadcast or multicast sibling. It is minimally viable but not rich enough to be fully contextual.

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 already documents all three parameters with 100% coverage, including the 'to' pattern and fallback, plus URL format and size limits. The description adds no parameter-level detail, so the baseline of 3 applies. The schema is doing the semantic heavy lifting.

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 action ('Send an image') and names the exact resource and target scope ('LINE user, group, or room'). This clearly distinguishes it from the sibling push_text_message, push_sticker_message, push_video_message, and other content-type tools. The singular target phrasing also differentiates it from broadcast and multicast siblings.

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 makes the use case clear: push an image message to a single LINE conversation, whether user, group, or room. It does not explicitly name alternatives or exclusion criteria, but the content type and target scope provide enough context to route an agent correctly. No misleading guidance is present.

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