add_collision_channel

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

Annotations already declare the safety profile (idempotentHint=true, destructiveHint=false, readOnlyHint=false), and the description adds genuinely new context: the side effect of consuming the next free ECC_GameTraceChannelN slot. The Returns block also enumerates observable outputs including an already_existed flag, which is useful since no output schema exists.

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?

Core purpose and the slot-allocation behavior are front-loaded in the first sentence, with the return shape kept to a compact single-line block. Slightly dense but no filler sentences.

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?

For a mutation tool with no output schema, the description compensates by listing the returned fields and flagging the idempotency semantics and slot side effect. The annotations cover reversibility; only explicit when-to-use/allocation-exhaustion behavior is left implicit.

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%, so the schema already documents all four parameters including defaults and the Block/Ignore/Overlap values. The description adds only that idempotency keys on channel_name, so 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?

Specific verb ('Register') plus resource ('custom project collision channel') with a distinguishing implementation detail ('claims the first free ECC_GameTraceChannelN slot'). An agent can immediately tell this is a creation tool distinct from the read-only collision siblings (list_collision_channels, diff_collision_channels, dump_collision_channels).

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?

The description implies the create/register use case and notes idempotency on channel_name, which helps an agent decide whether re-calling is safe. However, it never names a sibling or states when to use this over add_collision_profile or list_collision_channels, so guidance is only implied.

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