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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description adds substantive behavior on top: the file is validated first and nothing is saved if any line errors, and append mode deduplicates by adding only records not already present. It also makes explicit that replace mode overwrites the whole served file, which is exactly the destruction the agent needs to understand.

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 what is written and where, then the record grammar, then the atomic-validation rule, then the mode caveat. Four sentences, each carrying distinct information with no repetition of structured fields.

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 destructive write with no output schema, the description covers format, validation failure semantics, and mode behavior thoroughly. The only gap is that it never indicates what a successful call returns or confirms, which would be useful given there is no output schema.

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% and the schema already documents site (including the "habitly" short form), mode, and the enum. The description adds genuine meaning beyond that by spelling out the required line format with a concrete example record, which the schema leaves as just "The app-ads.txt lines."

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 and resource — writing the app-ads.txt file served at a concrete URL — and explains what that file is for (ad-network verification against the store listing). An agent can distinguish this from set_page or update_site without opening any 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?

The context for use is clear (ad networks check this file against the developer website in the store listing), and the mode=append semantics give a clear conditional. It does not, however, name when to prefer append vs replace or point to a sibling such as set_page for non-app-ads.txt content.

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