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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds genuinely new context: the listing spans the whole project on this account and includes sizes. The warning that site/vendor/ files are engines and SPOE-generated is real operational guidance an agent would not get from structured fields.

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 compact sentences, front-loaded with scope and return content, followed by the constraint. The 'SPOE' reference is unexplained but costs little space.

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 single-parameter read tool with no output schema, the description covers scope, a returned field (size), and a write-avoidance constraint. Pagination or ordering behavior is not mentioned, which is a minor gap.

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 project_id description already points to new_project, create_app, and list_apps as sources. The description says 'on this account' but adds no format or sourcing detail beyond what the schema provides, so the baseline 3 applies.

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 ('Every file in a project') and adds a return detail ('with its size'), so the agent knows it's an enumeration tool rather than the single-file read_file sibling. It never names read_file or list_apps explicitly, so differentiation is inferred rather than stated.

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 'read them, never write them' line gives indirect usage guidance for vendor/generated paths, but there is no explicit when-to-use or when-not-to-use versus read_file, write_files, or list_apps. The agent must infer that this is the discovery step before read_file.

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