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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real context beyond that: the data is scoped to a single post on a single platform and is functionally identical to a named MCP resource, which tells the agent this is a pure read with no side effects or cross-post aggregation.

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 compact sentences with zero filler: the first states exactly what is returned and how it is keyed, the second states the fallback condition. Front-loaded and appropriately sized.

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?

An output schema exists, so return values need not be described, and annotations carry the safety semantics. The only meaningful gap is the unmentioned post_type parameter and the nested 'request' wrapper, which the schema documents but the description does not surface.

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 description reinforces that lookup is keyed on post_id and scoped to one platform, which adds meaning for two of the three nested fields. However, it says nothing about post_type (FEED/REEL/STORY selection) or the fact that params are wrapped in a 'request' object, so it does not compensate for the reported low schema description coverage at the top level.

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?

States a specific resource ('full text and media of one post on one platform') and the lookup key ('by post_id'). It also names the exact equivalent resource URI, so an agent understands precisely what data it will get and how it maps to the MCP-resource counterpart.

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?

Explicitly names the alternative (the postey://posts/{post_id}/content/{platform} resource) and the condition that selects this tool: 'for clients that cannot read MCP resources.' That is a genuine when-to-use rule, though it offers no guidance relative to content-related siblings such as convert_post_content or validate_post_content.

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