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

Beyond the annotations, it discloses an important non-obvious behavioral boundary: "Only a link: the account's posts are not drawn with the character" – preventing a false expectation about post rendering. It also gives a verification path ("The account's `character_uuid` / `character_id` show in list_social_accounts"). It does not restate reversibility or permission requirements, which the destructiveHint=true annotation would otherwise leave ambiguous.

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?

One front-loaded sentence with a [write] marker, followed by three short clauses that each add distinct information (enum values, uuid provenance, unlink semantics, non-effect caveat). No filler or repetition.

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?

For a 3-parameter mutation with no output schema, the description covers what changes, how to undo it, where inputs come from, what side effects do NOT occur, and where to verify the result. Nothing an agent needs to call this correctly 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?

Schema coverage is 0%, so the description carries the full burden and does: it supplies the platform value set (ig|fb|tw|tt|yt|li|th|tg), the origin of `account_uuid`, the origin of `character_uuid`, and the special null/empty semantics that unlink the account. That is meaning the bare schema cannot convey.

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 opens with a specific verb+resource pair ("Link one of the merchant's characters to a connected social account") and immediately covers the inverse operation (`character_uuid` empty = unlink). It is unmistakably distinct from sibling tools like list_social_accounts or create_character.

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?

It states the two usage modes (link vs. unlink) and tells the agent where each uuid comes from (list_social_accounts, list_characters), which is practical routing guidance. It stops short of naming alternatives or exclusion conditions beyond the unlink case.

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