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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so safety is covered structurally. The description's only added claim, 'safe synthetic lab boundary,' vaguely gestures at the environment but doesn't say what is described, whether the token is required for richer output, or what the response contains.

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?

A single front-loaded sentence with no filler sentences or repetition. It is efficient, though the phrase 'safe synthetic lab boundary' is vague rather than informative.

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 and an undocumented optional parameter, the description needed to explain what 'describe' returns and what the token does. It supplies neither, leaving the agent unable to predict the result or know whether to pass credentials.

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?

The schema has one optional 'token' parameter with 0% description coverage, and the description never mentions it or its purpose (auth? optional identity?). With low schema coverage the description was expected to compensate and does not.

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 verb (describe) and resource (Fathom), so the basic action is inferable, but 'its safe synthetic lab boundary' is vague phrasing that doesn't clarify what information is actually returned. It also gives no signal to distinguish it from siblings like fathom_help, fathom_status, or fathom_space.

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?

There is no indication of when to call this versus the many fathom_* siblings (fathom_help, fathom_status, fathom_space, fathom_space_context) or platform-level alternatives. The agent must guess from the name alone.

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