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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds the context that it reports credit status for the connected account, but doesn't disclose additional behavior such as whether the query itself consumes credits or how fresh the data is. It is consistent with annotations.

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?

Two sentences, with the core action first and the usage trigger second. No filler or repetition of schema/annotation content.

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 low-complexity read-only tool with one optional parameter, the description plus schema cover the essential calling context: what it does, when to call it, and how to supply account_id. It doesn't detail the response fields, but the use-case phrasing ('how many credits remain') gives enough for the agent to interpret the result. Minor gap: no explicit statement about whether credits are returned per account or overall.

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%, and the account_id parameter already has a detailed description explaining when to omit it, when to list accounts, and never to guess. The main description adds no parameter-level detail, but the schema carries the full burden, so the 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?

The description uses the specific verb 'Get' and names the exact resource 'LinkedIn InMail credit information' plus a scope ('for the connected account'). It also states the trigger use-case ('whether an InMail can be sent or how many credits remain'), which clearly distinguishes it from the many other linkedin_* siblings, none of which cover credits.

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?

It explicitly says 'Use when the user asks whether an InMail can be sent or how many credits remain,' giving a clear when-to-use. It doesn't name alternatives or exclusions, but among siblings there is no competing credits tool, so the absence of when-not is not a major gap.

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