stickers_create_guild_sticker

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

Annotations indicate readOnlyHint=false, destructiveHint=false, and idempotentHint=false, which already imply a mutating, non-idempotent operation. The description adds value by stating the multipart upload method (though that's in the purpose) and explicitly warns that Discord rejects payloads that don't match file_format. It also mentions the return object structure. However, it does not disclose auth requirements, rate limits, or side effects beyond the operation, which could be expected for a creation tool, but the provided behavioral cues are strong enough to earn a 4.

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 well-structured with clear sections: Purpose, When to use, When NOT to use, Example, and Returns. Each section is concise and purposeful. The critical information (purpose and usage conditions) is front-loaded. There is no redundant text. The example is compact but illustrative.

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 7 parameters with 100% schema coverage, an output schema, and annotations. The description covers the essentials: purpose, usage boundaries, example, and return format. It does not delve into edge cases like multipart encoding specifics or handling of audit_reason, but given the schema + output schema richness, the description is sufficiently complete for an agent to call it correctly. A 4 is appropriate; a 5 would require more detail on multipart prerequisites or error conditions.

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%, so parameters are well documented in the schema. The description adds value by providing a concrete example with all required parameters, illustrating the expected format for file_data (base64 data URI) and file_format (numeric constant). This goes beyond the schema's descriptions and helps the agent construct valid calls. Since coverage is high, the baseline is 3, and the example pushes it to 4.

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 clearly states the purpose: 'Upload a new custom sticker to a guild (multipart).' It identifies the resource (guild sticker) and the action (upload/create new), and it is distinct from sibling tools like stickers_modify_guild_sticker and stickers_delete_guild_sticker. The purpose is unambiguous.

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 provides explicit 'When to use' and 'When NOT to use' sections. It clearly states not to use for modifying existing stickers, referencing the alternative stickers_modify_guild_sticker, and warns about format mismatch with the file_format field. This gives an agent clear guidance on when to invoke this tool versus alternatives.

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