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

readOnlyHint=true already establishes the safety profile, so the description's job is to add context beyond that — which it does by disclosing sort order (newest first) and that messages render with the form's own field labels. It omits pagination/auth details, but those are secondary here.

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, zero filler, and the core capability plus the usage trigger are front-loaded. Every clause earns its place.

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 return-shape burden and does so adequately by specifying ordering and label rendering. It leaves the site parameter's identifier format and result volume/pagination unstated, which is a minor gap for a read tool.

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 67%: form and limit already carry descriptions (including default 20 / max 200 and omit-for-all semantics), while site is undocumented in both places. The description's 'all the site's forms' only echoes the schema's form parameter, adding no new syntax or format detail, so the baseline 3 holds.

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 (read) and resource (messages sent through a site's contact forms) plus ordering and presentation. The 'This is the inbox' framing cleanly separates it from siblings like list_forms (which enumerates forms, not submissions) and set_form.

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?

Gives an explicit when-to-use trigger: 'use it when the person asks whether anyone has written in.' It implicitly contrasts with list_forms/set_form via the 'inbox' framing, but does not name an alternative tool or any when-not condition outright.

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