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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuine behavioral context beyond that: results are quoted from each platform's help pages with source links, and values a platform does not publish are returned as null. This provenance and null-handling disclosure is exactly the kind of extra signal that helps an agent interpret results.

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?

Front-loaded with the resource and payload contents in one dense sentence, followed by a short rules sentence about nulls and the omit-platform behavior. Every clause carries information, though the first sentence is long enough to be slightly crowded.

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?

With no output schema, the description carries the burden of describing returns, and it does so adequately (pixel limits, file size, formats, content rules, source links, null semantics). For a simple read-only, single-optional-param reference tool this is close to complete; only the relationship to sibling tools is left unstated.

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% and the enum is fully enumerated, so the schema already documents the single parameter. The description's 'Omit platform to get all' largely restates the schema's 'Optional: one platform; omit to list all', adding little beyond what is structured.

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 verb+resource (retrieve official profile/cover photo requirements) and enumerates exactly what the payload contains (pixel limits, file size, formats, content rules) across named platforms. It is clear enough to distinguish from a photo-auditing tool, though it never names the siblings audit_headshot or get_headshot_guide to sharpen the boundary.

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?

Usage is implied by the domain (fetch requirements when you need spec data), and 'Omit platform to get all' clarifies the parameter-driven behavior. However, there is no explicit when-to-use guidance versus audit_headshot (which evaluates an image) or get_headshot_guide (which presumably provides guidance), so the agent must infer the routing.

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