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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered structurally. The description adds behavior the annotations cannot convey: a 64 KB combined read limit, elevated OAuth because of private content, an account-bound computer:write scope, and possible prompted local owner approval. Those are exactly the preconditions an agent needs before calling, and none of them contradict the read-only annotation.

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 tight sentences lead with the operation and its limits, then the alternative, then the auth preconditions. Nothing is padding. Minor duplication exists between 'requires elevated OAuth due to private content' and 'Requires account-bound computer:write OAuth', which restate the same gate twice.

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 two-parameter read tool with no output schema and full annotation coverage, the definition supplies scope, limits, alternative routing, and auth gating. What remains unstated is how the response is shaped or what happens when the 64 KB budget is exceeded, leaving edge-case behavior to inference.

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 area, its enum, and the paths array are already documented, which sets a baseline of 3. The description still adds meaning beyond the schema by stating the 64 KB combined budget across all requested paths, a cross-parameter constraint the per-field schema cannot express. It does not clarify behavior when the budget is exceeded, which keeps it from a 5.

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 states a specific verb and resource (read text files), the batch scope (1-8 files), the containment constraint (one managed home area), and the aggregate size cap (64 KB). It also explicitly positions itself against the sibling exza_read_home_text, so an agent can distinguish the batch read from the single-file read 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?

It gives a concrete selection rule: use this for 1-8 files and use exza_read_home_text when reading a single file. That is a real routing instruction rather than implied usage. It stops short of covering other plausible alternatives such as exza_list_home_files, exza_search_home_files, or exza_read_workspace_file, so no explicit when-not guidance exists beyond the single-file case.

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