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

Annotations already declare readOnly=true, so safety is covered; the description goes further with edge directionality, hydration with endpoint summaries, and the temporal filtering rule for includeEnded (validTo in the past). This is meaningful behavioral context beyond the annotations.

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 dense sentences with zero filler. Return shape and the includeEnded toggle are front-loaded appropriately.

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 partially explains return content (edges hydrated with endpoint summaries), which is what an agent needs. Minor: it doesn't detail pagination or the summary fields, but that is a small 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 100%, so baseline is 3, but the description adds meaning to includeEnded beyond the schema's terse wording—clarifying that ended relationships have validTo in the past and are useful for historical questions.

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 and resource (list the typed edges touching one page), explicitly notes scope (both directions, hydrated with the other endpoint). An agent can distinguish this from compass_links_create/update/delete at a glance.

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 concrete usage context: 'understand a subject's neighborhood before adding to it' and 'who handled this before' for includeEnded. No alternative sibling is explicitly named, so it stops short of a 5, but the when-to-use scenarios are clear.

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