backend_render

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

With no annotations, the description carries the full behavioral burden and does well: 'offline' tells the agent no network or credentials are needed, and 'idempotent' signals it is safe to re-run. 'Prune supabase/' also discloses that files may be removed, which is important destructive context. It stops short of saying what happens on failure or whether existing files are overwritten.

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?

Purpose is front-loaded, then a compact colon-delimited list of side effects. It is one dense sentence, but every clause names a real artifact or trait, so there is little waste.

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?

An output schema exists, so return values need not be described, and the description covers offline/idempotent behavior plus the concrete mutation set. The main gap is placement in the broader setup pipeline relative to siblings like app_scaffold and backend_deploy.

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 0% and the single app_dir parameter is never named or described. The file paths and the app.spec.json reference imply app_dir is the project root containing those artifacts, which gives some implicit semantic value, but the description never compensates fully for the undocumented parameter.

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 action (rendering the backend to match app.spec.json) and enumerates the concrete artifacts produced: pruned supabase/, functions/_shared/app.gen.ts, config.toml, the CONTRACT.md quota block, legal sources, and listing.json URLs. This is far more specific than a sibling like backend_deploy, though it never explicitly names the alternative it contrasts with.

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?

Calling it a step that makes 'the scaffolded backend' follow the spec implies it runs after app_scaffold, so prerequisite order is inferable. However, there is no explicit when/when-not guidance and no mention of how it relates to backend_deploy, app_inject_config, or app_sync_spec, so the agent must infer sequencing.

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