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

Beyond the readOnlyHint/openWorldHint annotations, the description adds real behavioral context: the daily cap semantics, the reset timing, and the credit economics (balance, 1 credit per post, 15 with a link, plus packs) with the failure mode spelled out. This is information an agent cannot get from the annotations or schema.

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 primary answer, then layers in the X-credit detail and the usage cue. Every sentence earns its place except the trailing 'Read-only.', which merely restates the annotation.

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?

There is no output schema, so the description carries the return-value burden and does: it names remaining count, reset time, and the xCredits fields. Nothing an agent needs to call or interpret this tool is missing.

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?

Single parameter with 100% schema description coverage, and the schema already points to list_accounts as the source of the id. The description adds no format or constraint detail beyond the schema, so the baseline of 3 applies.

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 and what it returns: remaining posts available today, the reset time, and X-specific xCredits details. This clearly distinguishes it from siblings such as get_platform_capabilities (static capability info) and validate_post.

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 says to check it before a batch of create_post calls and explains the consequence of not doing so (an X post fails without enough credits). No alternative tool is named and there is no explicit when-not-to-call, which keeps it below a 5.

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