Add changelog entries

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

The description explicitly states 'calling it twice for the same version appends, it does not replace' — i.e. the tool is NOT idempotent, since two calls produce a different state than one. The annotations declare idempotentHint=true, so the description directly contradicts the structured metadata. This is the kind of inconsistency that can lead an agent to skip duplicate-safety checks it actually needs.

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?

Three short sentences, front-loaded with the action and followed by the two facts an agent most needs (append semantics, write gating). No filler and no restatement of the title.

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 mutation tool with no output schema, the description supplies the append-only semantics, the existential precondition, and the target scope. It stops short of describing failure modes (auth errors, rate limits, max-length rejection), but the essentials for calling correctly are present — the idempotency mismatch is a correctness defect rather than a missing-coverage one.

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 mod_id, version, changelog, and game_domain_name (including its default and max lengths) are already fully documented in the schema. The description only gestures at the same concepts ('changelog text for a version', 'your mods') without adding format, length, or default guidance, so the baseline 3 is appropriate.

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 pairs a specific verb ('Append') with a precise resource ('changelog text for a version of one of your mods') and a scope qualifier ('one of your mods'). It is immediately distinguishable from the read-side sibling nexus_get_mod_changelogs, so an agent needs no schema inspection to route correctly.

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 states an operational precondition ('Write operation (NEXUS_ALLOW_WRITES=true)') and the repeated-call behavior, which tells the agent when the call is viable. It does not, however, explicitly contrast itself with nexus_get_mod_changelogs for the read case, so there is no full when/when-not routing statement.

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