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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds real behavioral value beyond that: the histogram is computed over the full mars.graph_edge_catalog so newly added edge types appear automatically, and node_type optionally skips the type probe. It does not cover cost/latency or what happens for a node with no edges.

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?

The bolded opening statement front-loads the purpose, followed by the return contract, an example, a catalog note, and a prerequisite. Efficient overall, though the heavy backtick/JSON-in-prose formatting is a little dense for a short definition.

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?

There is no output schema, so the description must describe return values — and it does, enumerating node_id, node_type, name and the edge_summary fields with direction and count. Combined with the prerequisite and catalog behavior, an agent has what it needs to call and interpret it; only sibling differentiation and empty-result behavior are absent.

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 both parameters are documented there, including the enum, so the schema carries the load. The description only restates that node_id comes from graph_resolve and that node_type skips the probe — marginal added meaning, appropriate for the baseline 3.

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 resource (a graph node) and operation (detail lookup plus edge-type histogram), and spells out the exact return shape with a concrete MSFT example. It is clear what it does, though the phrase "what it's connected to" overlaps conceptually with siblings like graph_neighbors and graph_path, which the description never mentions or differentiates against.

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?

"Look before you leap" implies a pre-traversal inspection step, and it correctly points to graph_resolve as the source of node_id, which is genuine context. But there is no explicit when-to-use versus graph_neighbors/graph_path/graph_aggregate, and no stated exclusions, so the agent must infer the routing.

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