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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description still adds value by disclosing the breadth of content returned (five distinct route categories), which tells the agent this is a broad discovery read, not a narrow lookup. No pagination or size caveats are mentioned, which is the only gap.

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, front-loaded with the return payload and followed by the invocation cue. The route-type enumeration is information-dense rather than padded, though it could arguably be trimmed without much loss.

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 an output schema present, the description need not explain return structure, and the annotations cover safety and idempotency. What remains thin is the relationship to siblings with overlapping discovery scope (list_devices, get_device_docs), which is not addressed.

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 description coverage is 100%: slug and user_id are both documented in-schema, including an example for slug. The description adds no semantics beyond the schema (e.g., no note that slug must be one returned by list_devices), so the baseline 3 applies.

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+resource ('Return the OSC routes a device exposes') and then enumerates exactly which route categories come back (commands, cc/nrpn, sysex, note triggers, reply patterns). It is clearly device-scoped, which separates it from get_device_docs or list_devices, though no sibling is named explicitly.

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?

'Use this to discover what a device can do' gives a clear positive trigger for invocation. It stops short of stating exclusions or pointing to alternatives such as get_device_docs for documentation versus routes for capability, so an agent must infer the boundary itself.

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