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

Despite destructiveHint=true being set, the description adds substantial behavior: writes are ordered, capped at 64 KB each, eof causes EOF read, and seq makes retries safe (a taken seq writes nothing and says so). Those are exactly the operational facts an agent needs before invoking a mutation tool and are not derivable from the annotations or schema alone.

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?

Purpose is front-loaded in the first clause, and the parenthetical examples are compact rather than padded. It is dense — several constraints packed into two sentences — but every sentence carries a distinct constraint (ordering, size cap, seq retry, eof, read path), so little is wasted.

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 6-param mutation tool with no output schema, the description covers what to write, ordering, size limits, idempotent retry, and how to read the reply via briq_exec_result. It does not say what an error response looks like or whether concurrent writes from multiple callers are serialized, which would round out the picture.

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 already 83%, so the baseline is 3. The description goes beyond by explaining the seq contract (last value plus one, sourced from briq_exec_result) and the eof/read-EOF consequence, plus that base64 is used instead of data. That is meaningful added meaning, though the data vs base64 mutual exclusivity rule could be stated more sharply.

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 — writing to the stdin of a command started with briq_exec async and stdinOpen — and names the concrete message types (follow-up, answer, approval) plus the underlying wire formats (stream-json line, JSON-RPC). This makes it unambiguous against siblings like briq_exec, which starts commands, and briq_exec_result, which reads output.

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?

Explains the context that triggers use (a command already started async with stdinOpen) and routes the agent to briq_exec_result for reading the response. The 'use eof:true to close' guidance is conditional and explicit. It lacks an explicit 'do not use this to start a command — use briq_exec' exclusion, which keeps it below 5.

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