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

With no annotations, the description carries the full burden, and it does disclose useful operational context the schema cannot: pay-per-call pricing of $0.01 in USDC on Base. It also enumerates the normalization passes. However, it says nothing about idempotency, whether the original text is returned unmodified on failure, or the return shape, so the behavioral picture is only partial.

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?

A single dense sentence that front-loads the verb and operation list and appends the cost signal with no wasted words. Every clause earns its place.

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 stateless text transformer with 100% schema coverage the description is close to sufficient, and it usefully adds pricing. It still omits what comes back (normalized string) and how the options parameter alters behavior beyond one example, leaving a modest gap given no annotations or output schema exist.

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%, with 'text' documented (Persian value, max 100000 characters) and an options example already embedded in the schema, so the baseline is 3. The description's mention of 'digits' loosely hints at the options flag but adds no syntax or default information beyond what the schema supplies.

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 verb (Normalize) plus the resource (Persian text) and enumerates the transformations performed (Arabic->Persian letters, ZWNJ, spacing, digits), which lets an agent distinguish it from narrow siblings like fa_digits or fa_fixRtl. It stops short of explicitly naming which sibling to prefer, so it is clear but not fully differentiated.

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?

There is no when-to-use or when-not-to-use guidance and no routing to alternatives. An agent must infer that this is the broad, multi-step cleanup tool versus the single-purpose siblings, which is left entirely unstated.

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