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

Annotations only flag destructiveHint=true; the description goes further by spelling out the exact destructive mechanism (REPLACES the whole bucket, omitted keys are deleted) and the safety boundary (Runtime counters never overwritten). That is materially more than the annotation conveys.

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?

Three sentences, each load-bearing, with the destructive replace warning front-loaded before the scope exclusion and the config pointer. No filler.

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 destructive 3-param write with no output schema, the description covers the mutation semantics, the read-modify-write pattern, the un-writable scope, and where key validation lives. Nothing needed to invoke it 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 100%, so the schema already documents bucket, values and title_id, including the replace-whole-bucket and JSON-encode notes. The description mostly restates the destructive replace semantics rather than adding new per-parameter meaning, though the pointer to TitleCustomData config does add validation/TTL/default context. Baseline 3 is appropriate.

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 (write) and resource (the authored/Static part of the title's key-value data store), and explicitly distinguishes it from the Runtime scope and from save_title_custom_data. An agent can tell it apart from get_title_data and save_title_custom_data without opening either schema.

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?

Gives an explicit workflow prerequisite (read with get_title_data first, send it back extended), an explicit exclusion (Runtime scope cannot be written here; owned by CloudCode scripts), and routes the agent to save_title_custom_data for key registration. This is exactly the when-to-use / when-not-to-use guidance the dimension asks for.

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