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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, but the description still adds real substance: env vars are returned as names only, never values, and the run history is capped at 'last few' with time/status/duration. It also redirects the agent elsewhere for code and env values, which prevents a wasted follow-up call.

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, no filler, and the core identity ('One function's status') is front-loaded. The first sentence is a long comma-chained enumeration, but each item is distinct return-value information rather than padding.

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, the description carries the burden of describing returns and does so field by field, plus a pointer to where code/env values live instead. Missing only edge-case behavior (e.g. what happens if the function slug is unknown), which is minor for a read-only lookup.

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%, so site_id, function, and user_goal are already fully documented in the schema, including provenance hints ('from list_sites', 'from list_functions'). The description adds no parameter-level meaning beyond that, which is the expected baseline when the schema does the heavy lifting.

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 names a specific verb+resource ('One function's status') and enumerates exactly what comes back: deploy status, env var names, accessible data, recent runs. It implicitly contrasts with the sibling list_functions by scoping to a single function, but never names that sibling or any other alternative explicitly.

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?

Usage is only implied by the content list; there is no explicit statement of when to call this versus list_functions, test_function, deploy_function, or get_render_diagnostics. The final sentence ('code and env values are viewed in the site's Functions screen') does draw a useful boundary on what this tool will not give you, which is more than nothing.

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