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

Annotations already declare readOnlyHint, destructiveHint:false and openWorldHint:false, so 'Read-only' merely restates structured data. The description adds no behavior beyond that — nothing on what happens with a malformed or unresolvable link, or how the three resource types differ in response.

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 short sentences, front-loaded with the action and its resource types. The trailing 'Read-only' is wasted space given the annotations already say so.

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?

A one-parameter tool with full schema coverage and complete safety annotations needs little, but with no output schema the description should indicate what a read returns for each of the three link kinds. That gap leaves the agent guessing about response shape.

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% and the schema already gives example link formats and the id fallback, so the schema does the heavy lifting. The description contributes one useful nuance — the link must be passed verbatim as the person holds it — but no additional format or validity guidance.

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) plus the resolvable resource categories: proposal, join request, or the person's own memory. The 'by its link' framing distinguishes it from list/search siblings like fathom_find or fathom_space, though it never names those alternatives directly.

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?

'Given exactly as your person has it' implies the precondition (you must already hold a link) but never states when to prefer this over fathom_find, fathom_space, or fathom_remember. Usage is inferable rather than stated.

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