Update Facebook Page Cover Photo

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

The description adds behavioral context beyond the annotations: it requires pages_manage_metadata permission and explains the no_feed_story behavior. The annotations already indicate readOnlyHint=false and idempotentHint=true, and the description's 'Updates' aligns with these, so there is no contradiction.

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 a clear opening line and a compact Args block. Each parameter line is informative, and the mutual-exclusion and permission notes are valuable. It is slightly longer than strictly necessary because it repeats schema content, but it remains focused and easy to scan.

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 there is no output schema, the description covers the main calling requirements: required parameter, optional parameters, mutual exclusivity, and permission. It does not describe the return value or failure cases, but for a straightforward update operation with idempotentHint=true, the provided information is largely sufficient.

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 83% (5 of 6 parameters are described), and the schema already documents each parameter. The description adds a critical mutual-exclusion rule ('Provide either cover_url or photo_id') that the schema alone does not enforce. However, response_format is absent from the description, though the schema covers it with enum and default values.

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 states a specific action and resource: 'Updates a Facebook Page's cover photo.' This clearly distinguishes it from related tools like meta_update_page_picture, which would handle the profile picture, and from general page updates via meta_update_page.

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 clear usage context: it specifies the required page_id, explains that callers should provide either cover_url or photo_id, and states the required permission. It does not explicitly name alternative tools or when not to use this tool, but the context is clear enough for an agent to proceed.

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