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

Annotations declare readOnlyHint=false, which is non-obvious for a transcript tool; the description explains exactly why, disclosing that a Premium read of an untranscribed video starts a transcription that draws on plan credits, then on-demand budget, and reports its charge. It further discloses sandbox scope (arcmira, ArcmiraError, console), execution limits (30 seconds, 40 API calls, 12,000 characters total, 3,000 per string, 100 items per array), and the shape of bounded JSON output. This is behavior an agent could not infer from annotations or schema.

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 content is valuable but delivered as two very long run-on sentences with repetition (podcasts appear multiple times) and a feature list that meanders before the mechanism. It is front-loaded on the user-facing benefit, which is good, but tighter paragraphing separating purpose, invocation, cost, and limits would make it scannable. Nothing is wholly wasted, though several clauses could be trimmed without 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?

There is no output schema, and the description compensates fully by specifying the output envelope (result first, then call count, rate limit, build, capped logs) and the exact caps. For a code-execution tool with billing side effects, it also covers sandbox globals, time/call budgets, and credit consumption, which is everything an agent needs to invoke it safely.

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 both parameters are already documented. The description nonetheless adds meaning beyond the schema: what identifiers are in scope inside the function body, what a return value looks like, two concrete call forms (arcmira.transcript(url, { start, end }) and (await arcmira.search({ query })).chunks), and that filters accept entity, channel or video ids. That materially raises the chance of a correct first invocation.

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?

The description names a concrete resource and outcome: YouTube/podcast transcripts, exact quotes with the second they were said, timestamped watch links, and speaker attribution. It also discloses the underlying mechanism ("Runs a JavaScript program against the Arcmira API through the arcmira client"), which distinguishes it from arcmira_execute_write and arcmira_describe. The only weakness is placement: the general-purpose execution nature is buried in the second half after a narrow-sounding feature list, so the top line undersells what the tool actually is.

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?

Clear triggering condition is given: "Use Arcmira when the user shares a youtube.com or youtu.be link, or asks what a YouTube video or podcast said." It also points to arcmira_describe for other methods and examples. What is missing is an explicit exclusion versus arcmira_execute_write (i.e., when the task is a mutation, use the write tool instead), so the boundary is implied rather than stated.

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