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

With no annotations provided, the description carries the full burden and does so: it discloses the viewer-role permission requirement, the 404 behavior for unmatched slugs, the exact empty-surface return value, and the sandboxed rendering context. These are exactly the traits an agent could not infer from the schema.

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?

Front-loaded with the action, then context, then selection rules, then error/permission details — a sensible ordering. Five sentences with little waste, though the surface-kind framing is slightly verbose given it repeats what surface_slug's schema description already implies.

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?

No output schema exists, so the description usefully describes the return shape ({html, css, js}) and the empty case, plus auth and 404 conditions. It does not address what happens if the slug points to a non-html surface kind, a minor remaining 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%, so baseline would be 3, but the description adds meaning beyond the schema for surface_slug by spelling out the default-to-primary behavior and the empty-result case. The workspace `slug` parameter is left to the schema, so it is not a full 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?

States a specific verb+resource ('Read an HTML surface's body') and immediately characterizes what an HTML surface is (three text fields rendered in a sandboxed iframe). This clearly distinguishes it from siblings like update_html, create_surface, and list_surfaces.

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 enumeration to list_surfaces, explains the omit-vs-pass semantics of surface_slug, and names the concrete use case (confirm a surface shows the intended content before sharing its link). No inference required.

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