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

With no annotations, the description carries the full behavioral burden. It contributes one useful trait — the body is discarded, implying a non-echoing shape/count check — but says nothing about side effects, permissions, error behavior, or what is actually returned for nine heterogeneous inputs.

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 description is six words and front-loaded, but it is drastically under-specified for a nine-parameter tool with no annotations and no output schema; brevity here reads as omission rather than efficiency.

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 tool exposing nine unrelated input types with zero annotations and no output schema, the description explains neither what a caller gets back nor how the disparate parameters relate to the 'field-id count' purpose. It is far too thin to guide correct invocation.

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 each parameter (many with 'discarded after…' notes). The description adds no parameter-level meaning beyond that, which is the expected baseline when the schema does the heavy lifting.

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 phrase 'Thrift field-id count, body discarded' names an action (count) and a resource (Thrift field-id), so it is not pure tautology. However, it only accounts for one narrow facet of a tool whose schema accepts nine unrelated inputs (git ref, URL, city, RSS feed, hostname, JSON, file path, timezone, query), leaving the actual scope unclear and arguably misleading.

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?

There is no statement of when to use this tool, when not to, or which sibling (of the many *-ok / *-shape validators such as validate-json, file-path-ok, domain-shape) it replaces. The agent is given no routing information at all.

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