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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false, so safety is covered. The description adds the useful scoping fact that results are advertiser-bound identities usable for ad creation, but says nothing about result volume, pagination, or whether disabled identities are included — modest added value over the annotations.

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 short sentences with zero filler, and the definition of the resource is front-loaded before the usage hint. It is efficient, though the brevity borders on under-specification given the tool has three parameters.

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 should at least hint at what comes back (identities with IDs usable in create calls), which it does only obliquely via "needed to create ads." Parameters and safety are fully covered elsewhere, so nothing critical is missing, but the return shape and the account-optional behavior are unexplained.

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 all three parameters (folder, account, language) are documented in the schema, including the enum semantics for language. The description contributes nothing about parameters, so the baseline 3 applies rather than a higher score.

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 names the resource precisely and even defines the term ("TikTok accounts or custom display names") plus its scope ("the advertiser can run ads as"), which is enough to distinguish it from siblings like tiktok_campaigns or tiktok_audiences. The only gap is that the verb is implicit — it never says list/retrieve, so an agent infers a read from the noun phrase and annotations.

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?

"An identity is needed to create ads" implies this is a prerequisite lookup before tiktok_create_ad, but the description never names that sibling or states the dependency explicitly. There is no when-not guidance and no mention of how this differs from list_accounts, which is a plausible confusion point.

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