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

Annotations only declare the safety profile (readOnlyHint=false, openWorldHint=true, idempotentHint=false); the description goes well beyond that by disclosing the credit-consuming side effect of Premium reads of untranscribed videos, charge reporting, the sandbox scope, and hard execution limits (30s, 40 calls, output caps). This is exactly the supplementary behavioral context annotations cannot carry.

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?

A single dense paragraph that is well front-loaded: purpose, then capability list, then input/output contract, then limits. It is long but nearly every clause carries load; minor redundancy with the schema on the execution scope keeps it out of the top band.

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 carry the return contract, and it does: bounded JSON with the result first, then call count, rate limit, build, and capped logs, plus per-string/array caps. Combined with limits, credits, and error names, an agent has everything needed to call and interpret this 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 description coverage is 100%, so 'code' and 'intent' are already fully documented, and the description's restatement of the async-function-body contract largely duplicates the schema. It adds no per-parameter syntax, format, or example beyond what the schema provides, so the baseline of 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 and resource ('Runs JavaScript against the Arcmira API through the arcmira client') and then enumerates the exact data domains reachable (transcripts, mentions, sponsors, coverage, monitors). An agent can distinguish this from arcmira_execute_write without opening either schema.

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 routing guidance ('Methods and examples: arcmira_describe') and a precondition for filters (entity, channel, or video IDs required). It does not state when to prefer arcmira_execute_write instead, so the read/write boundary is left to the tool name.

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