status

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

Annotations already declare readOnly, idempotent, non-destructive, and openWorldHint=false; the description reinforces the last one with the concrete promise of no model-provider network calls, which is meaningful cost/latency context rather than repetition. It also characterizes the payload (session spend and savings), which is behavioral detail not present in the 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, no filler, with the capability enumeration front-loaded and the network-call caveat placed correctly as a secondary qualification. The comma-separated list is dense but each item is load-bearing, so nothing could be cut without losing information.

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?

Return values need not be spelled out since an output schema exists, and the safety profile is fully covered by annotations. The description covers what is inspected and the no-network guarantee. The one real hole is the unexplained `project_dir` argument, which leaves a caller guessing on an otherwise complete definition.

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?

The single `project_dir` parameter has 0% schema description coverage and a bare empty-string default, so the description is the only place its meaning could be conveyed — yet it is never mentioned. The agent cannot tell whether project_dir scopes the workspace reading, affects spend accounting, or is optional in practice.

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?

A specific verb ('Show') tied to an enumerated resource set: mode, model, thinking level, workspace, key presence, and session spend/savings. An agent can tell exactly what comes back. It stops short of 5 because it never distinguishes itself from the sibling `stats`, which plausibly overlaps on the spend/savings portion.

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?

Usage is only implied — an agent infers this is the cheap diagnostic/configuration check, aided by 'Makes no network calls to the model provider' which signals it is safe and low-cost to call. There is no explicit 'use this when X, use stats/consult when Y', and no stated prerequisite or trigger condition.

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