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

Annotations declare readOnlyHint=false but destructiveHint=false, and the description usefully explains this combination: it acquires the bundle but performs 'no host installation or immediate execution' and 'Keeps source/license'. That added context explains why a mutating tool is non-destructive, though it doesn't say where the acquired bundle lands.

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 tight sentences with the core action front-loaded and the key constraint (no install/execution) second. No filler, though it is dense enough that a slightly clearer routing sentence would have helped.

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?

An output schema exists so return values need not be described, and annotations cover the safety profile. However, for a tool sitting alongside install_city_tools, read_city_tool and city_tool_catalog, the description omits how the acquired bundle relates to those next steps, leaving the workflow incomplete.

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 all three parameters (url, sha256, api_key) are already documented in the schema. The description's 'exact files SHA' merely echoes the sha256 field rather than adding format or verification semantics, so 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 names a specific verb (Fetch) and resource (public HTTPS JSON tool bundle) and distinguishes itself from the install path with 'no host installation or immediate execution'. It is clear enough to separate from siblings like install_city_tools, though it does not name any sibling explicitly.

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: 'no host installation or immediate execution' contrasts with install_city_tools, but there is no explicit when-to-use/when-not statement or named alternative. The agent must infer that this is the fetch-only step preceding installation.

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