Add a changelog fragment

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

Annotations declare readOnlyHint=false, so the mutating nature is already signaled; annotations do not contradict. The description adds behavioral context: fragments are 'unreleased' (they accumulate until a release tool consolidates them) and 'atomic', giving the agent a sense of scope and lifecycle. It doesn't detail response format or failure modes, but output schema and annotations cover some of this. Slight gap on what happens after creation, but the note about 'unreleased' is valuable.

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, front-loaded with the core purpose. The second sentence adds genuinely useful operational guidance (granularity and timing). Could arguably be trimmed but every word earns its place and nothing is redundant with the schema.

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?

With 10 parameters but full schema coverage and a present output schema, the description's job is modest. It communicates the invariance rules (atomic, unreleased, timing) which the schema cannot express. It doesn't spell out the relation types fully, but the schema fields (cards, decisions, related, issues) cover that. Reasonably complete for a create-oriented tool.

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 10 parameters have structured descriptions already. The description adds the 'atomic' and 'unreleased' framing that connects to title/body semantics, but doesn't itself explain individual parameters. Per the baseline rule, schema is doing the heavy lifting, so 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 states a specific verb+resource ('Create an atomic unreleased changelog fragment') and adds clear semantics: one fragment per user-visible change, written when the change lands rather than when release is cut. It also mentions relating to cards, decisions, or other records, which distinguishes it from siblings like project_changelog_patch (edits existing) and project_changelog_list (lists).

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?

The description gives clear timing guidance ('written when the change lands rather than when the release is cut') and the atomicity rule ('One fragment per user-visible change'). It implies the creation use-case distinct from patch/release siblings, though it doesn't explicitly say 'use list/patch instead when...'. The timing and granularity advice is useful, context-rich guidance by name.

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