fetch_device_file

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

No annotations are provided, so the description carries the full burden. It usefully discloses scope (non-database files, AppGroup container) and where ESM packages actually live, but omits whether the operation is read-only, size/error behavior, or permission requirements.

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 sentences, purpose front-loaded with the routing caveat second. Efficient with no obvious filler, though the second sentence is somewhat narrow relative to the tool's general scope.

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 and no annotations, the description adequately covers what is fetched and where, plus a key misrouting warning. It lacks return-format and failure-mode context, but is complete enough for a simple single-parameter read tool.

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 the single path parameter already has example values in the schema. The description adds no syntax or format detail beyond what the schema provides, so the 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 (Fetches) and resource (a specific non-database file from the iOS device's AppGroup container), and the 'non-database' qualifier plus the named sibling get_rewrite_script_package lets an agent distinguish it from related tools without opening schemas.

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?

Explicitly routes the agent: for ESM rewrite script packages, use get_rewrite_script_package instead, and warns not to look for RewriteScripts/*.js files. This is a clear when-not/alternative for one important case, though it doesn't address other siblings like fetch_binary_payload or fetch_system_logs.

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